Introduction
In this module, you will learn more about the medical terms associated with the respiratory system. When you complete this module, you should be familiar with terms that describe the anatomy of that system and have a good understanding of terms that specify disorders affecting the respiratory system. You will recognize terms for tests and procedures that are used to diagnose and treat respiratory system disorders, and you'll learn about categories of drugs used to improve respiratory function. As you work through this module, you may need to refer to the basics of word structure that were introduced in Module 1.
Remember that this integrated learning program is intended as a supplement to your text—not as a substitute. Be sure to keep your text available for ready reference.
Objectives
In this module, you will learn to:
- Recognize names of the structures of the respiratory system and define terms associated with these structures.
- Sequence the flow of air from the atmosphere through the respiratory structures.
- Distinguish between structures of the upper respiratory tract and the lower respiratory tract.
- Identify the functions of external respiration.
- Name lung cancer as the leading cause of cancer deaths in the
- Write the meanings of word parts associated with the respiratory system and use them to build and analyze terms.
1.1 Normal Respiration (animation)
From 12 to 18 times every minute, we unconsciously perform an activity that is vital to our survival. That activity is breathing, the exchange of oxygen and carbon dioxide between our bodies and the external environment. The organs of the respiratory system make breathing possible.
The respiratory system also moistens and warms the air we breathe, aids in the production of speech, and helps to regulate the composition and balance of body fluids.
1.2 Threaded Case Study: Miguel
As we prepare to learn about the respiratory system, let's meet Miguel Escobedo. Miguel, 51, has been employed for 20 years at a large automotive plant. He works in the parts department, retrieving supplies for automotive assembly. Recently, Miguel was asked to visit with the plant physician because of his absences from work. Miguel reports to the doctor that he has had difficulty breathing and becomes fatigued easily as he climbs, bends, and walks to obtain the requested auto parts. We'll return to understand more about Miguel's health problems shortly. Now let's review the respiratory system.
1.3 Structures of the Upper Respiratory Tract
The respiratory system is divided into the upper and lower respiratory tracts. The structures of the upper respiratory tract include the nose, pharynx, adenoids, tonsils, epiglottis, and larynx.
1.4 Nasal Cavity
The nose is the entry point for air to travel through the respiratory system to the lungs. The combining form nas/o means nose, and nasal means pertaining to the nose. Other terms based on nas/o include endonasal and intranasal, both of which mean within the nose; retronasal, meaning behind the nose; and supranasal, meaning above the nose.
The interior of the nose is called the nasal cavity. It is separated by a midline partition, called the nasal septum. The nares are the nostrils, the openings to the nasal cavity.
A thin layer of mucous membrane lines the nose and is covered with fine hairs called cilia. This moist membrane warms, moistens, and filters the air as it flows toward the lungs.
Another combining form is used in medical terms to refer to the nose: rhin/o, which you'll see in terms introduced later in this module.
In addition to its function in the respiratory system, the nose is also the sense organ of smell, also called olfaction. Olfactory means pertaining to the sense of smell.
1.5 Paranasal Sinuses
The paranasal sinuses are air-containing cavities in the bones around the nose. They, too, are lined with mucous membrane. The paranasal sinuses produce secretions that drain into, and lubricate, the nasal cavity. These air-filled spaces also help to lighten the bones of the skull and serve as resonating chambers for speech.
Paranasal will be an easy term to remember because you know that para- means around and nasal means pertaining to the nose.
1.6 Palate
Beneath the nasal cavity is the oral cavity, the mouth. The combining form or/o means mouth.
Forming the floor of the nasal cavity and the roof of the mouth is the palate. The anterior portion of the palate is bony and is called the hard palate. The posterior portion is called the soft palate. It is the flexible, fleshy portion. The combining form for palate is palat/o; palatine means pertaining to the palate.
The small, dependent portion of the soft palate that hangs like a droplet at the back of the mouth is called the uvula. One combining form for uvula is uvul/o. You may recall from Module 7 that staphyl/o also refers to the uvula. Staphyl/o is from the Greek term that means cluster, and the uvula hangs from the soft palate somewhat like a cluster of grapes.
1.7 Pharynx
From the nasal cavity, air passes into the pharynx, a tube-like structure about 5 inches in length. The pharynx is also called the throat and is indicated in medical terms by the combining form pharyng/o. It serves as a passageway both to the stomach for food and to the lungs for air. The pharynx is divided into three sections.
The uppermost section is the nasopharynx, located just posterior to the nasal cavity. Contained within the nasopharynx are the adenoids, paired masses of lymphatic tissue that, along with the tonsils, help to eliminate bacteria, especially organisms that invade the body through the nose and mouth.
The second division of the pharynx is the oropharynx, which lies just behind the mouth and is the location of the tonsils. The combining form or/o means mouth.
The third section of the pharynx, the laryngopharynx, opens into the larynx and into the esophagus, an organ of the digestive system.
1.8 The Larynx
The larynx, also called the voice box, forms another part of the vital airway to the lungs. It is represented by the combining form laryng/o.
The location of the larynx is identifiable externally by the protuberance in the anterior neck, more prominent in men than in women, known as the Adam's apple.
1.9 The Epiglottis
In addition to warming, humidifying, and filtering incoming air, the larynx contains the vocal cords. Laryngeal muscles function to widen and narrow the opening between the vocal cords known as the glottis. As air is expired through the narrowed glottis, it causes the cords to vibrate, producing sound.
A leaf-shaped flap of tissue, called the epiglottis, covers the entrance to the larynx to prevent the aspiration of food into the airway during swallowing. The term aspiration refers to the process of drawing in or out by suction.
Notice the construction of these anatomical terms. The combining form glott/o means glottis; adding the prefix epi-, meaning above or upon, creates the term epiglottis, the structure that overhangs the larynx like a lid. Epiglott/o is the combining form that means epiglottis.
2.1 Trachea, Bronchi
The lower respiratory tract consists of the trachea, all the segments of the bronchial tree, and the lungs. With the exception of the trachea and the proximal portions of the main stem bronchi, the lower airway structures are contained within the lungs.
The trachea, or windpipe, is a cylindrical tube in the neck and upper chest, measuring approximately 5 inches in length. It extends from the larynx and divides at its lower end into two large air passages called the bronchial tubes or bronchi. The left bronchus enters the left lung and the right bronchus, which is slightly larger and more vertical than the left, enters the right lung. Each bronchus then divides into smaller and smaller branches, the smallest of which are the bronchioles.
The presence, in a medical term, of the combining form trache/o tells us that the term refers in some way to the trachea. Bronch/o and bronchi/o indicate the bronchi, and bronchiol/o tells us that a term describes a condition, characteristic, procedure, or disorder of the bronchioles.
2.2 Alveoli
The bronchioles branch to form microscopic tubes called alveolar ducts. It is from these ducts that the alveoli (sing., alveolus), clusters of millions of minute air sacs, arise. The alveoli lie in contact with capillaries. Oxygen moves through the thin alveolar walls into the bloodstream to be carried to tissues throughout the body. Similarly, carbon dioxide enters these air sacs from the capillaries to be exhaled. You'll note the combining form alveol/o in medical terms that refer to the alveoli.
2.3 Lungs
The lungs are the main structures of the respiratory system. They are cone-shaped organs. The pointed upper portions are called the apices (sing., apex) and the broader, lower portions are called the bases. The depressions in the medial surfaces where the main stem bronchi and the blood vessels enter the lungs are called the hila (sing., hilum). The term hilar means pertaining to one or both hila.
Each lung is divided into lobes, indicated by the combining form lob/o. The right lung has three lobes: upper, middle, and lower; the left lung has only two lobes: upper and lower. Together, this pair of highly elastic organs provides an enormous surface area for the exchange of oxygen and carbon dioxide.
The abbreviation for oxygen is O2, and the combining form that indicates this vital element may be either ox/i or ox/o. Carbon dioxide is abbreviated CO2; its combining form is capn/o.
Three combining forms mean lung: pulmon/o, pneum/o, and pneumon/o. Pneum/o also means air.
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2.4 Diaphragm, Mediastinum (animation)
The lungs lie within the chest, or thorax, and extend from above the collarbone to rest on the diaphragm, the muscular partition that separates the thoracic and abdominal cavities. You will recall that the combining form meaning thorax is thorac/o. The combining form for diaphragm is phren/o.
As we inhale and exhale, the diaphragm moves up and down, helping us to breathe. The thoracic cavity has three divisions: the mediastinum and the right and left pleural cavities. You will recall from previous modules that the central portion of the chest cavity, the space between the lungs, is the mediastinum. It contains the heart, trachea, esophagus, bronchial tubes, major blood vessels, and other organs. The combining form that means mediastinum is mediastin/o.
The pleural cavities are the spaces within the thorax that contain the lungs.
2.5 Pleura
The lungs are enclosed in a membranous layer, called the pleura, that fold over to also form the lining of the chest wall. The portion of the pleura closest to the lungs is called the visceral pleura; the part of the membrane lying next to the chest wall is known as the parietal pleura. The space separating the layers of the pleura is called the pleural space. It contains a small amount of fluid that helps to keep the lungs inflated and lubricated as they expand and contract during breathing. The appearance, in a medical term, of the combining form pleur/o tells us that the term refers to the pleura.
2.6 Threaded Case Study: Miguel
Let's look in on the progress of Miguel's examination. As Miguel describes his health history, we learn that he has been a cigarette smoker for the past 30 years. During the physical examination, the doctor notes that Miguel is thin but that his chest has a rounded appearance. Even climbing onto the examining table causes Miguel's breathing to become labored.
3.1 Normal Respiration (animation)
Respiration is the process by which oxygen and carbon dioxide are exchanged between the body and its environment. This exchange occurs at two levels.
External respiration describes the uptake of environmental air into the lungs, the passage of oxygen from the alveoli into the capillary blood, and the movement of carbon dioxide from the blood into the lungs for removal from the body.
Internal respiration occurs at the cellular level. It involves the absorption of oxygen by the body's cells from the blood and the elimination of carbon dioxide from the cells into the bloodstream.
3.2 Mechanics of Inspiration
Ventilation is the activity by which air moves into and out of the lungs. During the first phase of ventilation—inspiration or inhalation—air is drawn into the lungs. In these terms, the direction of airflow is signaled by the prefix in-, which here means in or inside.
When we inhale, the diaphragm contracts. Its downward movement increases the volume of the thoracic cavity. Contraction of the diaphragm causes pressure within the thorax to fall below that of the external environment. Because of this pressure difference, air flows from the atmosphere into the lungs.
3.3 Mechanics of Expiration
The second phase of ventilation is expiration or exhalation. During expiration, the diaphragm relaxes and returns to its normal position. This causes a reduction in the volume of the thoracic cavity and increases the pressure within it, forcing the air out of the lungs.
Once again, the direction of the airflow is indicated by the prefix. Ex- means out, without, or away from.
3.4 Acid-Base Balance
At the beginning of this module, you'll remember that we included, as a function of the respiratory system, the ability to regulate the balance and chemical composition of body fluids. Specifically, respiration helps to control the concentration of electrically charged hydrogen particles, called hydrogen ions (H+), in blood plasma.
Hydrogen ions are produced during the body's metabolic processes. When too many hydrogen ions are produced, the plasma becomes acidic as assessed by the pH scale, which indicates the concentration of hydrogen ions in a solution. If the concentration of hydrogen ions is too low, the plasma becomes basic or alkaline.
3.5 Acidosis, Alkalosis
The normal concentration of hydrogen ions in blood plasma lies within the range of 7.35 to 7.45 on the pH scale. Too many hydrogen ions can result in a condition known as acidosis. The combining form acid/o means acid. The increase in hydrogen ions in the blood is caused by an excess of carbon dioxide, usually when breathing does not provide adequate ventilation and this gaseous waste is not exhaled. An excessive amount of carbon dioxide in the blood is called hypercapnia. The suffix –capnia refers to carbon dioxide. One way in which the body may counter this state is by increasing the respiratory rate, a response that eliminates carbon dioxide and decreases the level of acid.
In alkalosis, there are too few hydrogen ions. This condition may be caused by hyperventilation, excessive respiration that depletes the carbon dioxide level in the blood and tends to cause respiratory depression. A decrease in the respiratory rate leads to an elevation in the level of carbon dioxide and the formation of acid, which restores the acid-base balance. The combining form alkal/o means alkaline or basic.
3.6 Threaded Case Study: Miguel
The plant physician suspects that Miguel's breathing difficulty is due to interference with the process of gas exchange. He suggests that Miguel have a series of chest x-rays and other special tests to assess how well his lungs are functioning.
3.7 Respiration
Respiration is a complex activity on which our survival depends. It involves a series of carefully regulated processes—ventilation, gas exchange, and gas transport—and relies on the interdependence of many body systems for its effectiveness.
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1.1 Upper Respiratory System
As we've learned, the nose, pharynx, larynx, and trachea form a vital passageway to the lungs. Because of their proximity to our external environment, these structures are common sites of infection and inflammation caused by incoming pathogens.
Allergic reactions and physical irritation can also cause inflammation of these organs. Another group of disorders, obstructions of the nose and throat, cause concern because of their ability to impede the process of breathing. Many terms that describe disorders affecting the upper airway are constructed from word parts.
1.2 Rhinitis
Rhinitis—from the combining form rhin/o and the suffix -itis—is an inflammation of the mucous membranes of the nose, usually accompanied by swelling of the membranes and a nasal discharge.
In its acute form, rhinitis is more often referred to as the common cold. Rhinitis may be complicated by inflammation of the paranasal sinuses, a condition known as sinusitis.
1.3 Pharyngitis
Pharyngitis, inflammation of the pharynx, can be either acute or chronic. Pharyngitis is characterized by symptoms that may range from slight scratchiness of the throat to severe pain. Based on your knowledge of word building, can you construct the term that is used to describe inflammation of both the nose and the pharynx?
1.4 Tonsillitis
If you guessed that nasopharyngitis is the term that means inflammation of the nose and pharynx, you're right!
You'll recall that both the adenoids and the tonsils are located within the pharynx. Inflammation of the adenoids is known as adenoiditis. Tonsillitis is inflammation of the tonsils, which, when inflamed, appear red and swollen. During the course of this disorder, the tonsils may enlarge to such an extent that they threaten to obstruct the pharynx.
1.5 Laryngitis, Epiglottitis
Just as the structures of the nose and pharynx can become inflamed, so too can those of the larynx. Laryngitis is inflammation of the mucous membrane lining the larynx. The swelling of the vocal cords that accompanies laryngitis causes the characteristic hoarseness called dysphonia, or loss of voice, which is termed aphonia.
The combining form phon/o means voice. Note the difference between phon/o and phas/o, which, you may recall from previous modules, means speech. Disorders identified as speech disorders are usually caused by conditions of the brain, whereas those related specifically to the voice are caused by conditions of the larynx.
Epiglottitis, as you can tell from the word parts, is inflammation of the epiglottis, the structure that covers the opening of the larynx.
1.6 Tracheal Stenosis
A variety of causes can result in inflammation of the trachea, a condition known as tracheitis. If both the larynx and trachea are inflamed, we use the term laryngotracheitis to describe the condition.
Another disorder affecting the trachea, which may require emergency intervention, is described by adding the suffix -stenosis to the combining form trache/o, creating the word tracheostenosis, a narrowing or constriction of the trachea.
1.7 Pertussis
Pertussis is a highly contagious upper respiratory infection (URI). Also known as whooping cough, pertussis is characterized by sudden periodic attacks, or paroxysms, of coughing, followed by a whooping inhalation. Childhood immunization against this infectious disease is very important
1.8 Influenza
Influenza, commonly called flu, is another very contagious and potentially fatal infection of the respiratory system. Influenza is categorized as type A, B, or C, depending on which of three viruses is responsible for the infection. Types A and B cause flu epidemics almost every winter. The disorder usually has a sudden onset and is characterized by fever, chills, headache, muscular aches, cough, and sore throat. Treatment seeks to relieve symptoms and prevent complications.
Persons at risk for contracting influenza and its complications are advised to receive an influenza vaccine annually.
1.10 Obstructive Sleep Apnea
Sleep apnea, often referred to as obstructive sleep apnea (OSA), is an interruption of airflow caused by the relaxation and repetitive collapse of the pharyngeal muscles during sleep. Symptoms of the disorder include loud snoring, frequent awakening at night, choking and gasping on awakening, and daytime sleepiness.
You'll recall that the suffix –pnea means breathing and the prefix a- means without. Therefore, this term that has no word root means without breathing and refers specifically to the periods of arrested respiration caused by this condition. When airway obstruction causes apnea, the individual moves or awakens, activating the pharyngeal muscles and restoring respiration.
1.11 Croup (audio)
Croup is a condition that results from the acute obstruction of the larynx due to swelling of the lining of the upper airway. This inflammation and obstruction can be caused by an allergen, bacterial infection, or foreign object, but is usually a response to viral infection. Croup affects children 3 years old and younger. Its symptoms include labored breathing; a harsh, barking cough; and stridor, a high-pitched sound that accompanies inspiration through blocked air passages.
1.12 Examination of the Nasal Cavity
Diagnosing disorders of the respiratory system involves integrating the reported symptoms with findings from a physical examination. Careful inspection of the respiratory structures is important, and endoscopic procedures such as laryngoscopy, pharyngoscopy, and tracheoscopy—visual examination of the larynx, pharynx, and trachea, respectively—may also prove useful.
Computed tomography is a useful imaging technique for examination of the larynx.
1.13 Treatment for Upper Respiratory Disorders
Treatment for disorders affecting the nose, larynx, pharynx, and trachea depend on the cause of illness and may range from bed rest to surgery. Some disorders may be relieved by the administration of medications, such as antibiotics and antihistamines. Antibiotics attack the cause of the illness. Antihistamines and decongestants address symptoms such as sneezing and congestion. Anti-inflammatory medications such as aspirin and acetaminophen control pain and fever. Medications available without prescription combine these types of drugs in preparations to treat colds, flu, and sinusitis.
1.14 Tracheostomy, Endotracheal Intubation
Life-threatening obstructions of the upper airway may require an emergency incision into the trachea, tracheotomy, and the creation of an artificial opening, called a tracheostomy, to provide a continuous airway.
Endotracheal intubation, the placement of a tube into the trachea through the nose or mouth, may be performed to maintain an open airway or to prevent the aspiration of food or secretions in persons with altered levels of consciousness.
1.15 Tissue Obstructions
Tissue obstructions of the respiratory structures are often treated surgically. For example, rhinoplasty is surgical repair of the nose to correct an anatomic problem, such as deviation of the nasal septum (as seen in the accompanying radiograph).
An inflamed organ may be excised, as in a tonsillectomy. Polyps are benign growths of the mucous membrane and may be surgically removed from the nose or larynx. This procedure is called a polypectomy.
2.1 Bronchitis
Analyzing and defining word parts allows us to form many terms that describe conditions affecting the bronchi. Bronchitis—from the combining form bronch/o and the suffix -itis—is a respiratory disorder in which inflammatory changes and narrowing of the bronchi cause airflow limitation (see illustration). Bronchitis may have an acute onset or may be slow, progressive, and continuous. Development of chronic bronchitis, which is characterized by a recurrent cough and excessive production of pulmonary secretions, is associated with cigarette smoking, infection, and inhaled irritants. An inflammatory condition of the bronchioles is referred to as bronchiolitis.
2.2 Imaging of the Chest
Diagnosis of chronic bronchitis may involve taking radiographic images of the chest; fiber-optic examination called bronchoscopy; examining laboratory cultures of sputum, the material expelled from the chest during coughing or clearing of the throat; measuring the amount of oxygen in the blood, a procedure known as oximetry; and spirometry, evaluation of the air capacity of the lungs.
Treatment may require the avoidance of irritants, including the cessation of smoking. Antibiotics and cough medications may be prescribed. Antitussives are cough medications that alleviate coughing by suppressing the cough reflex. Expectorants are cough medications that help raise mucus from the bronchi.
2.3 Threaded Case Study: Pulmonary Function Test
At the plant physician's request, Miguel is undergoing a series of tests, one of which uses the spirometer to measure and record the rate and volume of exhaled air. This examination is called spirometry and measures the rate and volume of air exhaled. It is one of a group of tests known as pulmonary function tests (PFT).
The combining form spir/o denotes breath or breathing; thus, a spirometer is an instrument that measures breath.
2.4 Bronchiectasis
In contrast to bronchitis, which involves a narrowing of the bronchial tubes, bronchiectasis is a respiratory disorder characterized by abnormal dilation of the bronchi. This condition is typically caused by bacterial infection. The infection weakens the walls of the bronchi. Purulent (pus-containing) material then collects within pockets of the damaged bronchial walls. Bronchiectasis may also be caused by an obstruction, beyond which the bronchial walls become distended.
2.5 Rales (Crackles) (animation)
Symptoms of bronchiectasis include a constant, productive cough and persistent rales, or crackles, abnormal discontinuous bubbling sounds heard during inspiration when the alveoli are filled with secretions. Rales do not clear with coughing.
Another abnormal sound heard in the chest on auscultation with a stethoscope is the ronchus (pl., ronchi), a rumbling sound that clears on coughing, indicative of liquid secretions within the bronchi.
Bronchoscopy, visual examination of the bronchi with a flexible, lighted fiber-optic tube called a bronchoscope, can be used to identify the source of secretions and evaluate the extent of the disease. Treatment for bronchiectasis includes the administration of antibiotics and special positioning of the body to promote secretion drainage.
2.6 Asthma (animation)
Asthma, also called reactive airway disease, is a chronic, intermittent respiratory disorder in which the air passages of the lungs become inflamed and over-responsive to a host of triggering agents. Exposure to pollutants, infection, cold temperatures, vigorous exercise, emotional stress, and certain medications can cause swelling and constriction of the bronchi as well as increased production and slow clearance of mucus.
Wheezes are whistling sounds that often accompany asthma. They are caused by narrowing of the air passages and can be heard during auscultation with a stethoscope. Coughing and dyspnea are also characteristic of asthma.
2.7 Bronchodilator
Pulmonary function tests (PFT) are a set of procedures used to measure airflow in and out of the lungs, including the spirometry that we saw Miguel undergo earlier. These tests can help to diagnose asthma and to determine the extent of airway obstruction.
Treatment for asthma includes avoiding known triggering agents and using medications such as bronchodilators. These medications may be taken orally or inhaled, as seen in this illustration. They improve breathing by relaxing the muscles of the bronchioles, expanding airway diameter, and aiding the clearance of mucus.
2.8 Cystic Fibrosis
Cystic fibrosis is an inherited disorder that affects the mucous membranes of the respiratory system as well as the pancreas and the sweat glands. In cystic fibrosis, the mucous glands produce thick, abundant secretions that cause airway obstruction. The disease is usually recognized in infancy or early childhood.
Although there is still no cure for cystic fibrosis, recent scientific breakthroughs have increased the life expectancy of those who have the illness.
2.9 Lung Cancer, Thoracotomy
Lung cancer is the leading cause of cancer death in both men and women. Most cancerous growths in the lungs originate in the bronchial passages. Lung cancer arising from the bronchi is referred to as bronchogenic carcinoma (Fig. A).
Diagnosis of the disease is established by identifying the malignant cells. An exploratory thoracotomy, an incision into the chest, allows microscopic examination of the suspected cells to confirm a diagnosis of cancer (Fig. B).
Lung cancer is curable only in those instances where surgery can be successfully performed. Lobectomy is the term for removal of a lobe of a lung; pneumonectomy is the surgical removal of an entire lung.
3.1 Atelectasis
Now let's look at some terms that describe conditions affecting the lungs and pleura.
Atelectasis is a disorder characterized by incomplete expansion or collapse of the alveoli. You'll recall that the combining form atel/o, which you can see in the term atelectasis, means imperfect or incomplete. Airway obstruction, by secretions or a foreign body, is a frequent cause of alveolar collapse. Compression from fluid or air in the pleural space, or a tumor in the lung, may also lead to collapse of the alveoli. Coughing and deep breathing exercises are necessary to prevent the acute onset of atelectasis following surgery.
3.2 Pneumoconiosis
The term pneumoconiosis describes a group of occupation-related lung diseases characterized by inflammation, infection, and bronchitis. These conditions are the result of inhaling irritants found in the workplace. For example, the accompanying illustration shows coal worker's pneumoconiosis or anthracosis, also known as black lung disease, which develops when coal dust is deposited in the lungs, forming black nodules on the bronchioles. Other types of pneumoconiosis include asbestosis, caused by the inhalation of asbestos particles, and silicosis, which develops from the accumulation of silica in the lungs. Treatment for pneumoconiosis depends on the signs, symptoms, and complications of each specific condition. Governmental exposure standards target prevention as a goal.
3.3 Pneumonia
Pneumonia is an acute inflammation of the lungs in response to infective agents, such as bacteria, viruses, and fungi. Smoking, the presence of pollutants, and a compromised immune system are among the predisposing factors for development of pneumonia.
3.4 Lobar Pneumonia, Bronchopneumonia
Pneumonia is characterized by high fever, chills, headache, coughing, and chest pain. The symptoms may vary in kind and severity, however, depending on the area of the lung involved in the disease process.
In lobar pneumonia, fluid, blood cells, and other debris consolidate, or solidify, within the alveoli of one or more lobes.
In bronchopneumonia, consolidation occurs primarily in the terminal bronchioles, affecting a smaller area and resulting in milder symptoms.
3.5 Chest Radiograph of Pneumonia; Percussion
A variety of diagnostic measures can help to detect and evaluate pneumonia. X-rays are taken to assess the distribution of the infection. Laboratory analyses of sputum and blood are performed. Physical examination using techniques such as percussion—tapping the body with the fingertips to determine the size, borders, and density of an internal organ—helps to reveal the presence of consolidation.
Treatment includes administration of antibiotics and analgesics and use of oxygen therapy.
3.6 Oxygen Therapy
As you'll notice throughout this section of the module, many respiratory disorders include, as part of their treatment, the administration of oxygen. This is required because many respiratory illnesses result in hypoxia, inadequate oxygen at the cellular level, and hypoxemia, decreased oxygen in the blood. Oxygen may be administered in a variety of ways: by oxygen mask, nasal cannula, or by transtracheal delivery; that is, directly into the lungs through a tracheal catheter.
3.7 Pleuritis
As you'll recall, the pleura is a membrane that enfolds both lungs and lines the chest wall. Pleuritis, also called pleurisy, is an inflammation of the pleura. The condition is characterized by dyspnea and chest pain. Common causes of the disorder include bacterial or viral infections such as pneumonia or tuberculosis. Pleuritis is also associated with pulmonary neoplasms, new growth of abnormal tissue in the lungs.
Treatment seeks to alleviate the pain and to address the underlying disease.
3.8 Pleural Effusion, Thoracentesis
Excessive fluid can accumulate in the pleural space as a consequence of infection, malignancy, or trauma. This condition, known as pleural effusion (Fig. A), results in fever, progressive dyspnea, and a nonproductive cough.
Chest x-ray and physical examination help to detect pleural effusion. A diagnostic thoracentesis (Fig. B), surgical puncture by insertion of a needle or catheter into the pleural space to obtain pleural fluid for analysis, is performed if the cause of the effusion is unknown. Treatment is aimed at the disease that caused the effusion.
3.9 Pneumothorax
Pneumothorax is a condition that involves the accumulation of gas or air in the pleural space between the lungs and chest wall, causing the lung to collapse. It may occur spontaneously or as a result of trauma. The onset of pneumothorax is accompanied by chest pain, rapid breathing, a weak pulse, dizziness, and a cough.
X-ray imaging of the chest reveals the presence of this disorder. Treatment involves administration of oxygen and aspiration of the air from the pleural space.
Now, using word parts that are familiar to you, can you think of a term that means blood in the pleural space? If you guessed hemothorax, you're right! Hemothorax requires emergency management to avoid shock and respiratory failure.
3.11 Emphysema
Now, let's continue our review of pulmonary disorders by considering emphysema, one of a group of illnesses collectively known as chronic obstructive pulmonary disease (COPD). In emphysema, the alveolar walls lose their elasticity, become overinflated, and eventually rupture. The disorder is strongly associated with cigarette smoking.
3.13 Barrel Chest
As emphysema progresses, more alveoli become distended, and the trapped air in the lungs results in development of the characteristic "barrel-chest." With loss of alveoli leading to ineffective gas exchange, breathing requires more effort.
3.14 Lung Tissue Damage with Emphysema
The damage to lung tissue seen in these illustrations occurs with emphysema and is an irreversible process. Progression of the disease can be slowed by elimination of causative factors, such as smoking. Therapeutic management may also include use of medication to improve breathing efficiency, breathing exercises, administration of oxygen, and, in some instances, surgery.
3.15 Threaded Case Study: Miguel
Miguel has returned for a follow-up visit with the plant physician to discuss results of his diagnostic tests. The doctor describes the results of the chest x-rays and pulmonary function tests, which reveal that Miguel has emphysema. He listens as the doctor recommends a smoking cessation program offered within the plant to employees. He and the doctor also talk about possible accommodations at work to ensure that Miguel is not exposed to occupational irritants. The plant physician is prescribing the use of a bronchodilator to address Miguel's symptoms now. He will continue to monitor Miguel to assess the need for oxygen therapy.
3.16 Tuberculosis
Despite being preventable and curable, tuberculosis (TB) remains a formidable public health problem in the
3.17 Post-Primary Tuberculosis
Once inhaled, the tubercle bacilli infect the lower respiratory tract, causing inflammation of the bronchioles and alveoli. The body responds to the bacterial invasion by marshaling the protective cells of the immune system and enclosing the bacilli in small, firm nodules called tubercles. During the early stages of the disease, while the organism is becoming entrenched, there may be few observable symptoms. As the disease progresses, night sweats, a chronic cough, lymph node enlargement, purulent sputum, weight loss, and fatigue may develop.
3.18 Acid-Fast Bacilli
Diagnosis of tuberculosis includes chest radiographs and laboratory examination of sputum. The diagnosis of tuberculosis is conclusive when the presence of acid-fast bacilli is detected in microscopic examination of a stained sputum smear (as illustrated). You will recall from Module 7 that the organism Mycobacterium tuberculosis is an acid-fast bacillus.
A combination of drugs is usually prescribed to treat tuberculosis because of the increase in drug-resistant strains of the TB bacterium.
3.19 Adult Respiratory Distress Syndrome
Adult respiratory distress syndrome (ARDS) is a disorder that usually develops as a result of physical trauma. The signs and symptoms of ARDS include rapid breathing, difficulty breathing, dry cough, fever, and cyanosis. Treatment involves administration of oxygen and prompt attention to the underlying cause of the disorder. Often, assistance with breathing must be provided with the use of a mechanical device known as a ventilator.
The pediatric equivalent of this disorder—known as respiratory distress syndrome of the newborn (RDS)—is manifested by airless alveoli, inelastic lungs, nasal flaring, and grunting. This condition is most often associated with premature birth.
3.20 Pulmonary Edema
Pulmonary edema occurs when abnormal amounts of fluid accumulate in the alveoli and interstitial spaces of the lungs. This condition is usually caused by fluid leakage from the pulmonary capillaries as a complication of heart disease. When the lymphatic system is unable to drain the excess fluid, it enters the bronchi and alveoli, interfering with gas exchange.
Pulmonary edema is a medical emergency requiring administration of medications to improve cardiac function, administration of oxygen to increase the oxygen level in the blood, and positioning to relieve breathing and improve blood flow.
3.21 Pulmonary Embolism, Pulmonary Infarction
Pulmonary embolism is blockage of a pulmonary artery (Fig. A). Often the cause of the blockage is a clot arising from a peripheral vein that breaks away, travels through the bloodstream, and lodges in the pulmonary vasculature. The symptoms associated with pulmonary embolism depend on the size of the clot as well as on the number and size of the occluded blood vessels. Common symptoms include sudden difficulty breathing, chest pain, and cyanosis. Interruption of blood supply to the lung can result in the death of lung tissue (Fig. B).
3.22 Lung Scan, Pulmonary Angiogram
Chest x-ray and lung scanning, the injection or inhalation of radioactive material to study its distribution in the lung, are procedures that help to screen for pulmonary embolism.
Pulmonary angiography, x-ray imaging of the blood vessels in the lung following injection of a contrast medium, is the definitive diagnostic procedure for this condition.
Treatment for pulmonary embolism involves use of thrombolytics, medications that dissolve clots and prevent further formation of emboli. For those unresponsive to medication, surgical intervention may be necessary.
Introduction
In this module, you will learn more about the medical terms associated with the digestive system. When you complete this module, you should be familiar with terms that describe the anatomy of that system and have a good understanding of terms that specify disorders affecting the digestive system. You will recognize terms for tests and procedures that are used to diagnose and treat digestive system disorders, and you'll learn about categories of drugs used to improve digestive function. As you work through this module, you may need to refer to the basics of word structure that were introduced in Module 1.
Remember that this integrated learning program is intended as a supplement to your text—not as a substitute. Be sure to keep your text available for ready reference.
Objectives
In this module, you will learn to:
- Match the structures of the digestive system with their functions.
- Match the four major functions of the digestive tract with their meanings.
- List the three classes of nutrients and their functions, and identify glucose as the major source of cellular energy.
- List the roles of the accessory organs of digestion.
- Write the meanings of the word parts associated with the digestive system and use them to build and analyze terms.
1.1 Threaded Case Study: Mrs. Kreider
To help us understand how the digestive system functions, let's meet Mrs. Kreider, who has come into the clinic for a routine exam. She does have mild problems with flatulence and some abdominal distention, but her intermittent bouts with both diarrhea and constipation are so widespread and inconsistent that she is not planning on mentioning them. She attributes these symptoms to dietary changes. We'll consider more of Mrs. Kreider's symptoms as we learn about digestive system anatomy and physiology.
1.2 Alimentary/Gastrointestinal Tract
The tube through which food passes from the mouth to the anus can be referred to as either the alimentary canal or the gastrointestinal (GI) tract. The digestive system includes the gastrointestinal tract and the accessory organs that support the process of digestion. Its principal function is to digest food, absorb and distribute nutrients, and discard solid waste byproducts.
1.3 Oral Cavity
The process of digestion begins inside the mouth, or oral cavity, where food is broken down both mechanically and chemically.
Try this experiment: Run your tongue over the roof of your mouth, near the front. You may detect ridges or rugae. Their texture can aid in crushing food in preparation for swallowing.
You will recall from the previous module that the roof of the mouth is called the palate and its combining form is palat/o.
1.4 The Tongue
Two combining forms mean tongue: gloss/o and lingu/o. The tongue aids in chewing, which is also called mastication, by grouping and repositioning the food between the teeth. These movements mix food with saliva to form a compact mass, called a bolus, and to initiate swallowing. As the food shifts around on the tongue's surface, it moves across the papillae (sing., papilla); these small raised areas contain the taste buds, receptor organs that detect specific types of flavors.
1.5 Tonsils
As you recall from previous modules, three pairs of tonsils are found in the mucous membranes on both sides of the back of the oropharynx, the portion of the throat (pharynx) near the mouth. The tonsils are small masses of lymphatic tissue that filter out harmful materials and produce lymphocytes (white blood cells) that fight disease.
1.6 Deciduous Teeth
Teeth are represented by the combining forms dent/i, dent/o, and odont/o. You can see that the common words dentist and orthodontist come from these combining forms.
In childhood we have twenty deciduous teeth, commonly referred to as our baby teeth. Children have two central incisors, two lateral incisors, two cuspids or canines, two tricuspids or first molars, and two second molars.
The term incisor is based on a familiar term, incise, meaning to cut. The purpose of incisors is to cut food; for example, the incisors act to cut a bite from an apple.
The cuspids are named for their pointed, pyramid shape.
1.7 Adult Teeth
In adulthood, we gain four bicuspids, or premolars, and two third molars, commonly referred to as wisdom teeth. Thus, in the adult, the upper and lower jaws each form a dental arch containing 16 permanent teeth, for a total of 32 permanent teeth in the entire mouth.
The bone of the upper jaw is called the maxilla. Its combining form is maxill/o, and maxillary means pertaining to the upper jaw.
The bone of the lower jaw is the mandible. Its combining form is mandibul/o, and the term that means pertaining to the lower jaw is mandibular.
Both maxilla and mandible have alveolar processes, which are the ridges in which the teeth are anchored.
The temporomandibular joints (TMJ) attach the mandible to the temporal bone of the skull on either side. Movement at these joints permits the opening and closing of the mouth.
1.8 Internal Structure of Tooth
Every tooth is structured in three basic parts: the crown, the neck, and the root.
The crown is covered with enamel to help it withstand the pressures and abrasions of mastication, or chewing. Just beneath the enamel are two more layers, the dentin and cementum.
As you can see in this illustration, dentin makes up most of the tooth's substance. It surrounds a pulp cavity containing connective tissue, blood vessels, lymphatic vessels, and nerves. This portion of the tooth is called the endodontium.
The tissues that surround and support the teeth are collectively called the periodontium. Their main functions are to support, protect, and provide nourishment to the teeth. The periodontium consists of cementum, the bones of the jaws, periodontal ligaments, and the gums.
The tissue that surrounds the tooth and helps to hold it in place is called the gingiva, or gum. The combining form gingiv/o means gum.
1.9 Periodontium
The tissues that surround and support the teeth are collectively called the periodontium, from the prefix peri-, meaning around, and odont/o, meaning tooth. The main functions of the periodontium are to support, protect, and provide nourishment to the teeth. The periodontium consists of cementum, the bones of the jaws, periodontal ligaments, and the gums.
The treatment of the periodontium is called periodontics. A dental professional who practices the specialty of periodontics is called a periodontist.
The gums, soft tissues that surround the teeth and help to hold them in place, are called the gingiva. The combining form gingiv/o means gums.
1.10 Salivary Glands
In the mouth, during chewing, the food is mixed with saliva, the first digestive juice to which it is exposed. Saliva contains enzymes that begin the process of converting starches to sugars.
Most of the saliva is released from the three extrinsic salivary glands (the parotid, submandibular, and sublingual glands), which lie outside the oral cavity and secrete into it.
The names submandibular and sublingual clearly indicate the location of these glands. Recall that mandibular means mandible and refers to the lower jaw. Lingu/o means tongue, and sub- means under or beneath. Thus, the sublingual salivary glands are located beneath the tongue and the submandibular glands are under the mandible.
The combining form bucc/o means cheek. The buccal glands are much tinier intrinsic salivary glands located throughout the oral cavity mucosa; they secrete less than 5% of the saliva. Nevertheless, their contribution is very important for the comfort and hygiene of the mouth.
1.12 Swallowing (animation)
Suppose, then, that our bolus of food has been chewed well, mixed sufficiently with digestive enzymes from the saliva, and swallowed. It will pass through the pharynx, or throat, first. The pharynx is really a muscle in the shape of a 5-inch-long tube that is lined with mucous membrane and that serves as a passageway not just for food, but also for air traveling to the trachea (windpipe) from the nose. In the previous module, you learned that the combining form for the pharynx is pharyng/o, and the term that means pertaining to the throat is pharyngeal.
Despite the sharing of this passageway, food does not fall into the trachea during swallowing, thanks to the epiglottis, a flap of tissue that moves to cover the trachea with each swallow.
Swallowing is called deglutition. It is the process by which the bolus of food enters the esophagus, a 10-inch-long tube that leads to the stomach. It is moved along through the alimentary canal by rhythmic contractions called peristalsis.
The combining form that means esophagus is esophag/o, and you will recall from previous lessons that gastr/o means stomach.
1.13 The Stomach
Sphincters, at both the upper and lower openings of the stomach, are circular muscles that contract to close these passageways and relax to open them. The cardiac sphincter at the lower end of the esophagus controls the passage of food from the esophagus into the stomach. This entry to the stomach is called the cardia or cardiac region because it is the portion nearest the heart. This also explains the name of the cardiac sphincter.
After entering through the cardiac sphincter, the food passes through three main sections of the stomach: the fundus, the body, and the pylorus (see illustration). The combining form for the pylorus is pylor/o.
Rigid folds in the stomach lining are called rugae. Glands within the rugae secrete hydrochloric acid and the enzyme pepsin to help digest the food, breaking it down so that it can be absorbed into the bloodstream from the small intestine.
The lower pyloric sphincter ensures that food does not leave the stomach and enter the small intestine until it is ready, both chemically and with respect to the size of the particles.
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1.14 Small Intestine
Although digestion begins in the mouth and continues in the stomach, the small intestine is the principal site of digestion and absorption. This is the first point in the digestive system at which nutrients begin to be absorbed for distribution to the rest of the body.
The bolus of food is moved along the 20-foot length of the small intestine by peristalsis. This passageway's coiled loops contain millions of tiny villi, microscopic fingerlike projections from the mucosal lining that are responsible for absorption of nutrients into the bloodstream and lymphatic vessels. The villi greatly increase the effective absorptive surface area of the small intestine.
The bolus first enters the upper section of the small intestine, the duodenum, where it is mixed with bile from the liver and gallbladder (GB) and with pancreatic juice from the pancreas. These enzyme-rich secretions further break the food down chemically before it passes into the 8-foot-long jejunum and then into the 11-foot-long ileum. The ileum is the third and final portion of the small intestine and attaches to the large intestine.
The combining forms for jejunum and ileum are jejun/o and ile/o, respectively.
1.15 Large Intestine
The large intestine, or large bowel, is 5 or 6 feet long and is noticeably larger around than the small intestine, measuring 2 1/2 inches in diameter, compared to the 1-inch diameter of the small intestine.
The large intestine is composed of three distinct parts: the cecum (cec/o), the colon (col/o, colon/o), and the rectum (rect/o). A bolus of food enters the large intestine through the cecum, a small pouch connected to the ileum (ile/o). A ringlike band of muscles opens and closes the opening between the two; this sphincter is called the ileocecal sphincter or the ileocecal valve. You can readily recognize the combining forms for both the ileum and the cecum in this term.
One notable thing about the cecum is that the sometimes troublesome structure called the vermiform appendix (wormlike) is attached to it. The vermiform appendix, which is usually referred to simply as the appendix (append/o, appendic/o), is a narrow pouch less than half an inch in diameter and 3 to 4 inches long. It has no known function. The term appendix means appendage or attachment.
From the cecum, the food bolus travels along the ascending colon. In the right upper quadrant near the liver, the ascending colon curves to become the transverse colon. On the opposite side, the colon turns in a downward direction and becomes the descending colon. In the left lower quadrant it forms its final S-shape, leading into the rectum; this portion is called the sigmoid colon after the Greek letter sigma, which curves like an S. The combining form for the sigmoid colon is sigmoid/o.
1.16 Rectum
After the material moving through the digestive system reaches the large intestine, the main component absorbed from it is water. As the material enters the large intestine, it moves through the colon to the rectum (rect/o). The term colorectal means pertaining to or affecting both the colon and the rectum.
Once the water is absorbed, this waste material is stored in solid form until it can be expelled from the body through the anus as feces. This process is called defecation. The suffix -chezia means defecation.
The combining forms for anus and feces are an/o and fec/o, respectively. For example, it would be correct to say that fecal material passes through the anal opening.
The combining form proct/o means anus or rectum and often refers to both. A proctologist is a medical specialist who diagnoses and treats disorders of the rectum and anus.
1.17 Peritoneum
Most organs of the digestive tract are held in place by a layered, serous membrane called the peritoneum. One layer, the parietal layer, lines the walls of the abdominal cavity; the second layer, the visceral layer, coats the organs themselves.
Note the fan-shaped projection of the parietal peritoneum, called the mesentery. This membrane holds the intestines in place but also allows sufficient free movement to prevent them from being strangled.
1.18 Threaded Case Study: Mrs. Kreider
Remember Mrs. Kreider? Her physician, Dr. Maldonado, has discovered that Mrs. Kreider has some tenderness in her lower left quadrant; she also has a slight fever. In addition, Dr. Maldonado notices abdominal distention, which Mrs. Kreider has assumed to be weight gain. With further questioning, Mrs. Kreider describes her mild problems with flatulence, diarrhea, and constipation. Dr. Maldonado discovers that Mrs. Kreider has an increased white blood cell count and tells her that he would like to do a sigmoidoscopy. This term comes from the combining form sigmoid/o and the suffix -scopy. Thus, we can see that it is a procedure that will use an instrument called a scope to help visualize the sigmoid colon. Another name for an increased white blood cell count is leukocytosis.
1.19 Bile Production (animation)
Several other organs also play an important role in digestion, even though they are not directly part of the digestive tract. The liver is the largest organ of the body and is represented by the combining form hepat/o. It is located in the right upper quadrant of the abdomen and has several important functions, one of which is the production of bile.
This yellowish or green liquid contains cholesterol, acids, and several pigments. The main function of bile is to aid in the digestion of fats.
Bile travels through the hepatic duct to the cystic duct, which leads into the gallbladder, abbreviated GB, a saclike organ on the inferior surface of the liver, where the bile is stored and concentrated. After a meal, the bile is forced into the common bile duct by the contraction of the gallbladder.
Both the common bile duct and the pancreatic duct enter the duodenum (duoden/o) at the ampulla of Vater. Here the bile and pancreatic enzymes form a partnership. Bile serves to emulsify, or break down, fat globules into small enough parts for the enzymes to digest.
The chief pigment in bile is bilirubin, a product of normal hemoglobin breakdown. Bilirubin is carried through the bloodstream to the liver, which conjugates it, combining it with other substances and adding it to bile so that it can enter the digestive tract for eventual elimination as a component of feces.
1.20 Pancreas
The final organ we should look at is the pancreas, a long, narrow organ that lies horizontally in the upper abdomen, surrounded by curvature of the duodenum (see illustration). This organ produces digestive enzymes and secretes them into the pancreatic duct.
At the same time that bile is secreted into the common bile duct, the pancreas secretes enzyme-rich pancreatic juices into the pancreatic duct. The pancreas also secretes insulin and glucagon, hormones that helps release sugar from the blood and glycogen from the liver, making energy-producing glucose available to the cells.
2.1 Threaded Case Study: Mrs. Kreider
Dr. Maldonado has discovered that Mrs. Kreider has some small herniations through the muscle layers of her colon wall. These are actually saclike outpouchings of mucosa.
"This," Dr. Maldonado tells her, "is undoubtedly what's been causing your symptoms!"
To further understand what Mrs. Kreider is experiencing, and to explore several other disorders, it is time to closely examine the primary function of the digestive system: to process essential nutrients and make them available to every cell in the body.
2.2 Metabolism (animation)
You will recall from Lesson 1 that the digestive tract is sometimes called the alimentary tract. The process of providing nutrition for the body is called alimentation. All of the processes the body undergoes to use the nutrients we feed it are referred to as the body's metabolism. Within that global process are two smaller phases.
Anabolism refers to the way our body converts these nutrients to build body cells and other needed materials. Catabolism is the opposite; it has to do with breaking down molecules into other useful substances.
2.3 Mechanical Digestion
Two kinds of digestion take place at the same time: mechanical digestion and chemical digestion.
Mechanical digestion begins with the ingestion of food, taking it into the mouth. It includes mastication, or chewing, and deglutition, which is the process of swallowing. Once food enters the esophagus, mechanical digestion also includes motility, the physical processes of propelling, breaking apart, and mixing.
Because the duodenum is so much smaller than the stomach, the stomach contents are ejected into the duodenum about every 20 seconds. Stomach motility is controlled by hormonal and nervous signals that prevent overloading the duodenum.
Once food enters the intestines, the two types of mechanical digestion are peristalsis, or forward movement (the suffix -stalsis means contraction), and segmentation, which is primarily a mixing movement.
2.4 Chemical Digestion
At the same time that mechanical digestion is occurring, chemical changes take place as the food travels through the digestive tract. This chemical digestion includes secretion of specific digestive enzymes.
Chemical digestion begins in the mouth where saliva mixes with the food in preparation for swallowing. The enzyme amylase in saliva begins the conversion of starch into glucose.
The stomach secretes hydrochloric acid, pepsin, and intrinsic factor that aid digestion, or absorption, of specific nutrients. These gastric juices are mixed with the partially digested food to form a creamy semi-fluid called chyme.
As chyme moves into the intestines, the pancreas releases enzymes, which are denoted by the suffix -ase. These include protease for digesting proteins and polypeptides, lipase for digesting emulsified fats, nuclease for digesting nucleic acids, and amylase that breaks down starches.
2.5 Chemical Secretions
As you learned in the previous lesson, the liver secretes bile, which is concentrated and stored in the gallbladder until it is needed for digestion. Bile emulsifies fats, increases the pH of chyme, and provides the means for excretion of cholesterol and bile pigments.
Finally, the intestines secrete mucus and water for mixing and lubrication and sodium bicarbonate to neutralize acid for optimum enzyme function.
Two types of laboratory blood tests that are used to assess liver function are SGPT (serum glutamic pyruvic transaminase) and SGOT (serum glutamic oxaloacetic transaminase). These tests identify enzymes normally present in the heart and the liver that are released into the blood whenever the heart or the liver is damaged. The group of laboratory analyses called liver function tests (LFT) also includes serum bilirubin and alkaline phosphatase.
2.6 Glycogenolysis and Gluconeogenesis
In addition to producing bile, the liver stores excess glucose (simple sugar; -ose means sugar) in the form of the starch glycogen. Glycogen is not found in plants; it is produced only in animals and humans. The combining form that means glycogen is glycogen/o.
The liver converts glycogen back into glucose when the blood sugar level drops. This process is called glycogenolysis.
Knowing that -ose means sugar, it is easy to deduce that lactose means milk sugar and fructose means fruit sugar (lact/o means milk and fruct/o means fruit).
Enzymes that convert these sugars, and other molecules as well, have names that are similar to the substances they act upon but end in the suffix -ase, which denotes that these substances are enzymes. Lactase, for example, acts upon lactose. Note carefully the slight differences in spelling of these terms.
The liver can also convert proteins (prote/o) and fats (lip/o) into glucose when the body needs sugar (glyc/o and gluc/o). This process of creating glucose from other molecules is called gluconeogenesis.
Besides all of these functions, the liver also manufactures blood proteins for clotting, releases bilirubin, and detoxifies the blood. The actual breakdown of protein is called proteolysis. An excess of fat in the blood is called hyperlipidemia.
2.7 Amylolysis
Starch (amyl/o) is easily broken down and reduced to glucose before being absorbed into the bloodstream. This breaking down or digestion of starch is called amylolysis.
You will recall that amylase, the enzyme that facilitates amylolysis, is present in saliva and begins the breakdown of starch before the food is swallowed. This process is continued with the help of additional amylase that is secreted by the pancreas.
1.1 Dental Disease
The most common pathologic condition of the mouth is dental caries, or tooth decay. Debris in the mouth combines with saliva and bacteria to form plaque, a film on the teeth that can soften tooth enamel and create a pit of decay called a cavity.
Recall from the previous section that the combining form gingiv/o means gums. Thus, gingivalgia means painful gums, and gingivitis means inflammation of the gums. Gingivectomy is surgical removal of diseased areas of the gum.
When gingivitis is unchecked and involves the periodontium, the condition is called periodontitis. Another term for this condition is pyorrhea, literally meaning discharge of pus.
Recall that gloss/o means tongue. Thus, glossitis is inflammation of the tongue, and gingivoglossitis refers to inflammation of both the tongue and the gums. Glossectomy is excision of all or part of the tongue, a surgical procedure that may be used to treat carcinoma of the tongue.
1.2 Mouth Sores
Two common conditions involve inflammation of the mouth. These two mouth sores are frequently confused, but their etiologies and appearances differ. The canker sore (top illustration), known as aphthous stomatitis, is idiopathic. Canker sores are small, painful lesions within the mouth.
The cold sore, or fever blister, (bottom illustration) is an inflammation caused by infection with the herpes simplex virus (HSV), thus its name herpetic stomatitis.
Stomat/o, like or/o, means mouth. Stomatomycosis is a fungal condition of the mouth. The combining form myc/o means fungus. Stomatoplasty is surgical repair of the mouth.
An inflammation of the lip (cheil/o) is called cheilitis. Cheilosis involves splitting of the lips due to a riboflavin deficiency in the diet, and cheiloplasty is surgical repair of the lip. Surgical repair of both the mouth and lip is called cheilostomatoplasty.
1.3 Cleft Palate
Cleft palate is a congenital condition in which the two sides of the palate fail to fuse during fetal development. It is sometimes accompanied by cleft lip, a split in the upper lip. Both of these conditions make it difficult to talk and to swallow, and they are usually corrected surgically soon after birth.
1.4 Salivary Disorders
You probably recall learning in Module 7 that a sialolith is a stone in a salivary gland or duct. Sialography is radiographic imaging of the salivary glands and ducts with injection of a contrast agent through a special cannula.
Be reminded again that sialaden/o is the combining form for salivary gland. Thus, sialadenitis means inflammation of one or more salivary glands.
The combining form parot/o indicates the parotid gland or glands. Thus, the term parotitis refers specifically to inflammation of the parotid salivary glands. Another name for infectious parotitis is mumps. At one time this was a common childhood disease, but immunization against mumps has greatly reduced the incidence of this disease.
1.5 Oral Leukoplakia
Less common, and distinguished from both canker sores and herpetic stomatitis, are white patches or plaque on the oral mucosa. This precancerous condition is called oral leukoplakia.
The risk of this condition is much higher in men than in women and is greatest in long-term smokers and users of smokeless tobacco.
Although this condition may become malignant, many people who have this condition do not develop oral cancer.
1.6 Gastroenterology
The study of the diseases that affect the alimentary tract is gastroenterology, as you may recall from Module 2.
Gastr/o means stomach and enter/o means intestines, as does intestin/o. Thus, gastric means pertaining to the stomach, and both enteral and intestinal mean pertaining to the intestines. Enteric is a synonym for enteral.
1.7 Eating/Swallowing Terms
Eating and swallowing are both represented by the suffix -phagia. For instance, an inability to swallow is called aphagia; difficulty with eating or swallowing is called dysphagia; and excessive eating, you've learned, is called polyphagia.
When a patient cannot chew or swallow food but can digest and absorb nutrients, enteral nutrition provides nutrients, bypassing the mouth. A nasogastric tube (NG tube) that passes through the nose, pharynx, esophagus, and into the stomach provides a route for supplying liquids. This tube can also be attached to a suction machine to empty the stomach. When long-term enteral nutrition is required, a feeding tube may be placed directly through the abdominal wall into the stomach (gastrostomy) or into the small intestine (jejunostomy).
The term parenteral means pertaining to a route other than the alimentary canal, so parenteral nutrition is that delivered intravenously. If long-term parenteral nutrition is required, an indwelling catheter may be surgically placed for this purpose. Total parenteral nutrition (TPN) refers to administration of all nutrition through an indwelling catheter. This method is also referred to as intravenous alimentation and hyperalimentation. You will recall that the term hyperalimentation is also used to refer to overeating or overfeeding.
1.8 Eating Disorders
Anorexia, or lack of appetite, can result from several very different factors. An- means no or without, and -orexia means appetite.
In its simplest form, anorexia may be a natural response to intense emotion. If the individual is very angry or very anxious, the body cannot simultaneously focus on both emotional responses and digestion. Thus, eating may be delayed temporarily.
But anorexia can also be abnormal. It can signal the presence of a condition such as malignancy or liver disease, or it may occur full blown and independent of other disease. In the absence of other causative factors, anorexia is considered to be an eating disorder called anorexia nervosa.
Bulimia is the term for a somewhat different eating disorder. This condition is characterized by cycles of craving bingeing, followed by purging through the use of laxatives or by vomiting (-emesis). Irritation or inflammation of the esophagus (esophag/o), a condition known as esophagitis, occurs with excessive vomiting, or hyperemesis, as seen in bulimia.
1.10 Obesity
While lack of food intake can be a serious health problem, overeating can also have a negative impact on health. Polyphagia and hyperalimentation are terms used to specify patterns of overeating.
The term adipose refers to fatty tissue; the combining form adip/o means fat. Obesity is an excess of body fat that can result in a significant impairment of health. Individuals whose weight is 30% or more above their ideal weight are generally considered to be obese. Obesity increases the risk of many health problems, including heart attack, stroke, hypertension, and diabetes.
When obesity is caused by excessive food intake, it is termed exogenous, meaning that the cause originates outside the body. Endogenous obesity originates within the body, usually as a result of endocrine disorders or uncontrolled diabetes.
Conservative treatment for obesity includes both diet and exercise. Drugs may also be prescribed to decrease appetite. These medications are variously referred to as anorexiants, anoretics, or anorectics.
When conservative methods are not successful, morbidly obese patients may be treated surgically. Gastroplasty and gastric bypass (demonstrated in the illustration) surgery are two methods with somewhat different goals. Gastroplasty reshapes or partitions the stomach, reducing its capacity and thereby reducing the quantity of food that can be consumed. With gastric bypass, the stomach is reduced in size and attached directly to the jejunum, reducing both capacity and absorption.
Surgical procedures to remove localized collections of fat for cosmetic reasons include lipectomy and liposuction. Lipectomy is excision of subcutaneous fat; liposuction is a technique for removing adipose tissue using a suction pump device.
1.11 Malaise
Although every disease is unique, some symptoms are frequently encountered in numerous disorders of the GI tract. We'll look at some of the most frequently encountered symptoms.
One common symptom of many problems of the digestive system is malaise. This term refers to a vague, uneasy feeling of bodily fatigue and discomfort, often marking the onset of disease and persisting throughout its course.
1.12 Vomiting Reflex
Nausea is often described as an unpleasant sensation in the throat or stomach. It results from irritation of specific nerve endings in the stomach that sends a message to the vomiting reflex center in the brain.
Nausea often, but not always, precedes vomiting, or emesis. Nausea and vomiting may be symptoms of a disease, organ perforation or obstruction, or may be a natural reaction to toxins in the stomach. Extraordinary stress can also produce these symptoms.
Excessive vomiting is termed hyperemesis. The treatment for this condition is a drug of the class called antiemetics.
The prefix dys- means bad, and the suffix -pepsia means digestion. Thus, dyspepsia is used to refer to any form of bad or difficult digestion. Normal digestion is called eupepsia (eu- means normal or good).
1.13 Diarrhea
Diarrhea is the frequent passage of loose, watery stools, usually occurring in response to a toxin or infection, and sometimes accompanied by abdominal cramping.
Antidiarrheals are medications that work to control diarrhea; there are several types that work in different ways. For example, some slow the passage of stools through the intestines, allowing more time for water and salts in the stools to be absorbed back into the body. Others absorb diarrhea-causing substances and pull them from the digestive tract. Still others decrease the secretion of fluid into the intestine and inhibit the activity of bacteria, relieving both diarrhea and cramping.
1.14 Constipation
In contrast to diarrhea, constipation is a decreased motility of the colon; defecation becomes difficult because the feces are dry and hard. For this reason, dyschezia, difficulty passing feces, is a common symptom of constipation. Slow peristalsis or inadequate diet can be a cause of constipation.
Several types of medications are prescribed to cope with constipation. Stool softeners are very mild medications used to prevent constipation. Laxatives cause evacuation of the bowel within 8 to 12 hours and are a relatively gentle treatment for constipation.
Strong medications that promote complete evacuation of the bowel are called cathartics or purgatives. They are used to prepare the lower intestine for surgery or diagnostic studies, such as barium enema or colonoscopy.
1.15 Malabsorption Syndrome
We should also consider malabsorption syndrome as an example of a group of symptoms often found together in response to the small intestine's failure to absorb nutrients.
The prefix mal- means bad; thus, malabsorption suggests poor absorption of nutrients. As nutrients are passed without absorption, the symptoms that occur include anorexia (depressed appetite), abdominal bloating, cramps, anemia, and fatigue.
Related to malabsorption is steatorrhea, which is the improper absorption of fats.
1.16 Gastrointestinal Bleeding
Bleeding is another symptom that can occur with a number of different disorders of the gastrointestinal tract; it can occur anywhere in the GI tract due to disease or injury.
The presence of bright red blood in the stool is indicative of a problem in the colon or rectum, often from hemorrhoids, which you will recall are dilated, varicose rectal veins. The illustration shows both internal and external rectal and anal hemorrhoids.
Melena, on the other hand, is the condition of black, tarry stools that usually means blood is coming from the upper part of the GI tract: the esophagus, stomach, or duodenum. Bleeding ulcers are often suspected when this condition is noted.
Another indication of bleeding in the upper portion of the gastrointestinal tract is vomiting of blood. The term for this condition is hematemesis.
Blood may be present in fecal waste even though it is not visible. Blood in feces can be detected by a laboratory test called the stool guaiac test or fecal occult blood test (FOBT).
1.19 Gastrointestinal Radiography
The classic radiographic procedures for evaluation of the lining of the gastrointestinal tract are fluoroscopic studies using a suspension of barium sulfate as a contrast medium and a type of x-ray machine that permits the radiologist to view the x-ray image in real time, demonstrating both structure and function. Moving pictures and still images can be recorded during these procedures.
Esophagram, esophogram, and esophagogram are terms for the fluoroscopic evaluation of the esophagus. This study is also sometimes called a barium swallow.
An upper gastrointestinal (GI) series (seen in the illustration) is a fluoroscopic examination of the esophagus, stomach, and duodenum, during and following oral administration of a barium sulfate suspension.
A lower gastrointestinal (GI) series is an examination of the colon, during and after the rectal administration of a barium suspension. This procedure is also referred to as a barium enema.
1.20 Endoscopy
Several previous modules have provided information about endoscopy, the general term for a wide range of procedures that involve the use of a tubular fiber-optic device that allows the physician to make a direct visual inspection of structures that are within the body and cannot otherwise be directly examined.
There are many variations in the design of endoscopes to suit them for specific purposes, and these individual designs have names that indicate their purpose. For example, a gastroscope is an endoscope designed for examination of the stomach. This specific procedure is termed gastroscopy.
Following this example, it is apparent that the combining form for an organ or body part, followed by the suffix -scope provides the specific name of the instrument used to examine the body part, and -scopy is used in the same way to name the specific examination procedure. Use this method to create the terms for instruments and procedures to examine the following portions of the gastrointestinal tract:
esophagus (esophag/o)
pylorus (pylor/o)
duodenum (duoden/o)
small intestine (enter/o)
colon (colon/o)
sigmoid colon (sigmoid/o)
anus and rectum (proct/o)
1.21 Pathology of the Esophagus
Now, let's look at several specific disorders of the gastrointestinal tract, starting with the esophagus.
You will quickly appreciate that esophagitis (esophag/o plus -itis) is the term for inflammation of the esophagus. This condition is often caused by irritation from the backflow of stomach contents, which are highly acidic, into the lower esophagus. When the cardiac sphincter fails to prevent this backflow, the condition is called gastroesophageal reflux disease (GERD).
Esophageal atresia is a congenital defect in which the esophagus is not open to the passage of food. The term atresia has both Greek and Latin roots and means without perforation. The esophagus may end in a blind pouch or be extremely narrowed. This condition is correctible surgically.
Achalasia is a relatively rare disorder of the esophagus characterized by failure of the cardiac sphincter to relax so that food can pass into the stomach and by the loss of peristalsis. These two conditions result in dilation of the esophagus. Achalasia causes difficulty swallowing, both solids and liquids, and frequent regurgitation of food. Symptoms may also include heartburn and cough. It can occur at any age but is more common in middle-aged and older adults.
Esophageal varices (sing., varix) (as seen in illustration) are unevenly dilated veins at the distal end of the esophagus. They occur as a result of hypertension in the portal circulation, the venous system that routes blood from the digestive tract through the liver for filtration before it enters the systemic circulation. Esophageal varices are a very serious condition because of their underlying cause and because they are particularly subject to hemorrhage.
1.22 Gastric Disorders
By now you are familiar with the combining form that means stomach, gastr/o, and with many of the suffixes that indicate abnormal conditions.
For example, gastropathy is the general term for any abnormal condition affecting the stomach, and gastritis means inflammation of the stomach. Gastromegaly is an abnormal enlargement of the stomach. This term is sometimes also used to refer to abdominal enlargement. Gastromalacia is the term for a morbid softening of the stomach. The term for cancer of the stomach is gastric carcinoma.
A very common condition affecting the stomach is called hiatal hernia. This is the term for protrusion of the stomach through the esophageal hiatus of the diaphragm and into the chest cavity. This is due to a widening of the diaphragmatic opening. Often a portion of the stomach moves back and forth through this opening depending on the position of the body and on whether the stomach is distended with food. Many people are unaware that they have this condition because often there are no symptoms, but GERD is a relatively common complaint. Hiatal hernia is diagnosed by means of an upper GI series and treated medically. Surgical correction is possible, but rarely necessary.
When gastroptosis, displacement of the stomach, is a significant problem, surgery called gastropexy is used to anchor the stomach to the abdominal wall. Suturing of the stomach is termed gastrorrhaphy, and partial or complete excision of the stomach is called gastrectomy.
1.23 Pyloric Stenosis
Pyloric stenosis, also known as infantile hypertrophic pyloric stenosis (IHPS), is the most common cause of intestinal obstruction in infancy. It occurs because of excessive growth (hypertrophy and hyperplasia) of the muscular layers of the pylorus. Infants with this condition become undernourished because milk cannot pass to the small intestine for absorption. Forceful vomiting may occur. Pyloric stenosis is corrected surgically by incision of the pyloric sphincter. The procedure may be called either pylorotomy or pyloromyotomy.
In adults, ulceration, or scarring caused by ulceration, can cause narrowing or constriction at the pylorus that prevents food from passing normally into the duodenum. Surgical repair of this condition is termed pyloroplasty (as seen in the illustration).
1.24 Ulcers
Perhaps one of the most familiar terms for disorders of the GI tract is the ulcer, an open wound or sore. An ulcer in the wall of the esophagus, stomach, or duodenum is called a peptic ulcer (PU).
Although most people would suspect that the stomach is the most common site of ulcer development, it is actually in the duodenum where these lesions are most likely to occur.
Ulcers are diagnosed using both x-ray procedures (upper GI series) and endoscopic studies (gastroscopy and duodenoscopy).
1.25 Untreated Ulcers
Ulcerous tissues, left untreated, will continue to erode the stomach or intestinal wall. Some ulcers are bacterial infections involving H. pylori and are treated with antibiotics.
Overproduction of hydrochloric acid in the stomach can cause or contribute to ulcer formation as well. When ulcers are identified early, drugs to reduce the production of hydrochloric acid can be very helpful. In severe cases, a surgical procedure called proximal gastric vagotomy is used to sever the branch of the vagus nerve that enervates the part of the stomach that secretes acid.
Although ulcers rarely lead to perforation and life-threatening hemorrhage, untreated ulcers can eventually cause anemia from persistent bleeding, even though it may be slight.
1.26 Dysentery
Dysentery is the term for several different diseases characterized by acute colitis (inflammation of the colon) and diarrhea, usually with blood and mucus. The most common types of dysentery are shigellosis, an infection caused by the Shigella species of bacteria, and amebic dysentery, infestation by an ameba, Entamoeba histolytica. Both of these types of dysentery are spread by fecal contamination of food and water and are most common where sanitation is poor. They are primarily diseases of the tropics but may occur in any climate.
Similar types of infections are commonly called food poisoning. One common form is salmonellosis, a foodborne illness caused by the bacterium salmonella. Symptoms include nausea, vomiting, abdominal cramps, diarrhea, fever, and headache.
1.27 Irritable Bowel Syndrome
Irritable bowel syndrome (IBS) is a functional disorder that is extremely common, affecting more than 10% of the population to some degree. The symptoms are constipation and bloating, alternating with episodes of diarrhea and cramping. The condition is often associated with emotional stress.
Other terms for IBS include spastic colon, mucous colitis, spastic colitis, and irritable colon (IC).
While medication is sometimes used to control symptoms, the best treatment for this condition is usually dietary modification and lifestyle change.
1.28 Ulcerative Colitis
Inflammatory bowel disease (IBD) is chronic inflammation of the digestive tract that can be painful and debilitating.
Ulcerative colitis is one of the two most common types of IBD. It is an autoimmune disease of the large intestine that may produce bleeding ulcers within the colon. It is an idiopathic, chronic, and recurrent disease.
1.29 Crohn's Disease
The other common type of inflammatory bowel disease is also an autoimmune disorder of the gastrointestinal tract and is called Crohn's disease. Crohn's disease is very similar to ulcerative colitis—so similar, in fact, that they're often mistaken for one another. Both inflame the lining of the digestive tract, and both can cause severe bouts of watery diarrhea and abdominal pain. But Crohn's disease can occur anywhere in the digestive tract, often spreading deep into the layers of affected tissues. Ulcerative colitis, on the other hand, usually affects only the innermost mucosal lining of the colon and the rectum.
This form of IBD is a more chronic intestinal inflammation than most and usually occurs in the terminal ileum and colon. The disease is characterized by weight loss, irritable bowel syndrome (IBS), and lower abdominal pain.
With Crohn's disease, inflammation leads eventually to fissures, or grooves, in the mucosa. Ulcerations begin in the intestinal mucosa and spread deep into the intestinal wall. Fistulae sometimes form as well. Fistulae are abnormal passages, either between two internal organs or leading from an organ to the surface of the body. You can see here, as you compare the normal bowel wall at the top with Crohn's disease below, how the multiple ulcers have formed a rough "cobblestone" texture.
1.31 Diverticulosis
A diverticulum is a saclike pouching in a wall of the gastrointestinal tract. It is actually a herniation through the muscle layer of the intestinal wall. These abnormal pockets occur most often in the colon. The plural form of diverticulum is diverticula and the combining form is diverticul/o.
The condition of having diverticula is called diverticulosis. This condition is quite common after the age of 50; it occurs most frequently in the sigmoid colon and is usually not symptomatic, although mild cramps, bloating, and constipation can occur.
The term diverticulitis contains the suffix -itis, indicating inflammation. In this more serious condition, the diverticula are accompanied by inflammation, causing pain and tenderness.
Complications of diverticulitis may include bleeding, infections, perforations or tears, or blockages. When infection is present, fever, nausea, vomiting, chills, cramping, and constipation may occur. The severity of symptoms depends on the extent of the infection and complications.
Dietitians advise patients to eat a variety of high-fiber foods to lower the chances of developing diverticulosis.
1.32 Threaded Case Study: Treatment for Diverticulosis
Let's return now to Mrs. Kreider. After examining the results of her sigmoidoscopy, Dr. Maldonado reports the presence of a number of small pouches in the colon wall. He explains that these are called diverticula.
Mrs. Kreider recalls that other women in her family have been treated for diverticulitis and wonders if she has this condition.
Dr. Maldonado says, "Well, at this point, we only know for sure that it's diverticulosis, but your elevated white blood count suggests the possibility of early diverticulitis. Prompt treatment and proper diet are essential to prevent complications."
Mrs. Kreider's therapy includes initial treatment with laxatives, gradually decreased as her symptoms improve, and increasing bran and fiber in her diet, as she needs fewer doses of laxative.
1.33 Ascites, Peritonitis
Ascites is an abnormal accumulation of serous fluid in the abdominal cavity (shown in the illustration). Ascites is not a disease, but rather a symptom seen with other serious disease processes. Liver disease and cancer of abdominal organs can cause this condition. Ascites may be alleviated by abdominal paracentesis, which you will recall is the surgical puncture of a body cavity for the withdrawal of fluid.
Peritonitis is the term for inflammation of the peritoneum, the membrane that lines the abdominal cavity. Peritonitis occurs as a result of a rupture or perforation of the digestive tract. Perforated ulcer, ruptured appendix, perforated diverticulum, or traumatic perforation permits bacteria from the digestive tract to enter the peritoneal cavity, which is usually a sterile environment. Peritonitis is a life-threatening condition and is treated aggressively with antibiotics.
1.34 Intestinal Obstruction
Intestinal obstruction is the term for a serious condition that blocks the alimentary canal, preventing food from passing. Obstruction may be partial or complete. There are many possible causes.
An obstructing condition that occurs in infants, but not in adults, is called intussusception, telescoping of the intestine within itself. This leads to swelling, inflammation, and decreased blood flow to the intestines involved.
Volvulus is a twisting of the bowel that causes obstruction. This condition occurs in infants and in adults.
Abdominal surgery, injury, or inflammation can heal with bands of scar tissue that bind intestinal surfaces together, preventing normal movement. These abnormal connections, most often affecting the small intestine, are called adhesions and are sometimes responsible for bowel obstruction.
Tumors are the most common cause of obstruction that occurs in the colon. Surgery is usually necessary to correct intestinal obstruction.
1.35 Gastrointestinal Surgery
Many types of disorders of the gastrointestinal tract can require surgery. Malignant tumors may occur at nearly any location throughout the digestive tract but are most common in the stomach and in the colon. In addition, other severe disorders, such as perforated ulcers of the stomach, duodenum or colon, or extensive and severe chronic ulcerative colitis or Crohn's disease, may also require surgery.
When a segment of the digestive tract is removed, the remaining portions may be connected surgically. This type of connection is called an anastomosis and is specifically named using terms to indicate the parts that are connected. For example, if a distal portion of the stomach is removed, the procedure is called a partial gastrectomy. The remaining portion of the stomach must then be attached to the first portion of the small intestine using the procedure called a gastroduodenostomy, the formation of a new opening between the remaining stomach and the duodenum. The illustration shows a subtotal gastric resection with gastroduodenostomy anastomosis. You'll recall that the suffix -stomy refers to the creation of a surgical opening. If the entire stomach was removed and the esophagus attached to the duodenum, the procedure would be called an esophagoduodenostomy.
When all or part of the colon is removed, the surgery is called a colectomy. The remaining portion of the digestive tract must then be routed to the outside of the body through the abdominal wall, forming an artificial anus, called a stoma, on the abdominal surface for the evacuation of feces. When a portion of the colon remains to form the stoma, the procedure is called a colostomy. When the entire colon is removed and the digestive tract terminates at the ileum, the procedure is termed an ileostomy.
2.1 Jaundice
Perhaps the two most notable diseases affecting the liver (hepat/o) are hepatitis and cirrhosis.
Hepatitis is inflammation of the liver caused by a viral infection that manifests itself through anorexia, malaise, abdominal discomfort, pale feces, and dark urine. Victims may also suffer joint pain. Severe cases cause nausea and jaundice, the yellow tint of body tissues, particularly the skin, mucosa, and sclera, that results when bilirubin (bile pigment) accumulates in the blood.
Jaundice is best recognized on the sclera, the tough, white outer covering of the eye. The sclera is normally white in all ethnic groups, but in those persons with jaundice, it becomes yellow. On further examination, the patient may have an enlarged liver or elevated liver enzymes, which would indicate liver damage.
2.2 Hepatitis A
There are five common types of hepatitis, classified A through E. Hepatitis A is the most common and results from a specific hepatitis A virus (HAV); it is transmitted by means of contaminated food or water.
Hepatitis A is an acute, self-limiting disorder and can become life threatening.
The hepatitis E virus (HEV) is also transmitted via food and water that is contaminated with the feces of infected persons. It is not common in the
2.3 Hepatitis B
Hepatitis B is caused by a bloodborne virus (HBV) and is almost always more severe than hepatitis A. It is sometimes referred to as serum hepatitis because it can be acquired parenterally through blood and body fluids.
Fortunately, a vaccine is available to provide immunity to those who are occupationally exposed to potentially infectious blood or body fluids as well as to patients who are at risk because they suffer from conditions that may be treated with blood transfusions. The risk of contracting the hepatitis B virus from a blood transfusion in the
The hepatitis D virus (HDV) is also bloodborne. It appears only as a co-infection with hepatitis B.
2.4 Hepatitis C
The hepatitis C virus (HCV) also is bloodborne and is contracted primarily through blood or blood products. It can also be acquired through sexual contact and, very rarely, through mother-infant transmission.
Even though hepatitis C is slightly more likely than hepatitis B to lead to chronic liver conditions, such as hepatic fibrosis and cirrhosis, these cases are not common, occurring only about 10% of the time.
2.5 Cirrhosis of the Liver
Cirrhosis is a degeneration of liver tissue. The severity of this disease is better understood when you realize that the liver is an organ known for its regenerative capabilities.
Cirrhosis occurs when toxicity levels are so high that regeneration cannot keep up and damaged portions are replaced with scar tissue, as shown in this photograph. These dangerous levels of toxicity can be caused by malnutrition, chronic alcohol abuse, or by infection such as hepatitis.
2.6 Hepatoma
You should be familiar with the names of a few additional conditions affecting the liver.
Hepatoma (seen in the illustration) is a specific type of primary liver carcinoma. This tumor may be removed by surgical incision into the liver, called hepatotomy, or by hepatectomy, the excision of part of the liver. Because the liver is essential for life, the entire organ cannot be removed unless a liver transplant is available.
Hepatomegaly is the term for enlargement of the liver, and hepatosplenomegaly is enlargement of both the liver and the spleen.
2.8 Diabetes Mellitus
You will recall from an earlier lesson in this module that one important function of the pancreas is the production of insulin, an enzyme that is essential to the body's ability to utilize glucose. The combining forms glyc/o and gluc/o mean sugar. Glycolysis is the breaking down of sugar.
Diabetes mellitus is a disease characterized by the inability of the body to metabolize glucose, usually as a result of inadequate insulin production by the pancreas. Without insulin, glucose levels in the blood increase dangerously. Hyperglycemia is the term for this condition; it literally means blood condition of excess sugar. Even though there is more than enough sugar in the bloodstream, the body cannot use it properly.
Symptoms of diabetes include weight loss and excessive thirst. The combining form that means thirst is dips/o; excessive thirst is called polydipsia. A lack of thirst would be called adipsia.
Diabetes mellitus is treated with diet, exercise, and medication such as insulin injections or oral hypoglycemic agents. Hypoglycemia is the condition of low blood sugar, so a hypoglycemic agent is one that lowers the blood glucose level.
When diabetic patients do not eat after they have received insulin, they may develop hypoglycemia, characterized by the sudden onset of weakness, sweating, quivering, and finally loss of consciousness. Some individuals who do not have diabetes also experience hypoglycemia.
2.9 Pancreatitis
We have seen how the pancreas, represented by the combining form pancreat/o, is responsible for the endocrine disorder diabetes, but the pancreas may be involved in other serious conditions, such as damage from digestive enzymes or alcohol. Stones from the biliary system may create a blockage of the pancreatic duct, causing inflammation of the pancreas.
Acute pancreatitis is a severe condition of inflammation characterized by pain, massive swelling, and bleeding. When the acute phase is past, this condition sometimes becomes chronic.
Removal of pancreatic stones is called pancreatolithectomy, and the procedure is often accompanied by pancreatography, imaging of the pancreas that involves injection of the pancreatic duct with a contrast medium for visualization on x-ray. If this radiographic study includes the bile ducts as well, it is called cholangiopancreatography.
2.10 Complications of Pancreatitis
Pancreatitis can lead to several types of serious complications.
One complication is the formation of pancreatic pseudocysts, like those shown here. They are collections of fluid around the pancreas. The fluid in the cyst is usually pancreatic juice that has leaked out of a damaged pancreatic duct. While this condition often resolves without treatment, surgery is required if it becomes severe.
Another complication of pancreatitis is pancreatolysis, destruction of pancreatic tissue by pancreatic enzymes. Normally these enzymes are not activated until they reach the small intestine, but when severe inflammation interferes with this process, the enzymes attack the pancreatic tissue and it literally begins to digest itself.
Necrosis, or tissue death, can occur as a result of either the inflammatory process or pancreatolysis. The necrotic tissue may be sterile or infected. If infected, the condition is more severe and more apt to spread. Surgery may be required to clear away the necrotic tissue.
Incision of the pancreas is called pancreatotomy; removal of all or part of the pancreas is called a pancreatectomy.
2.11 Gallbladder Disorders
The main disorder affecting the gallbladder is cholelithiasis, commonly referred to as gallstones. Another name for a gallstone is a cholelith. Attacks of severe pain, or biliary colic, occur when a stone blocks a duct.
We have noted that the combining form bil/i means bile. Similarly, the combining form chol/e refers to bile or gall. The combining form cyst/o means a bladder or sac, so combining both chol/e and cyst/o creates the combining form for gallbladder, which is cholecyst/o. Thus, cholecystitis is an inflammation of the gallbladder, and cholangitis is an inflammation of a bile duct.
Radiographic imaging of the gallbladder is called cholecystography and the image taken is called a cholecystogram. Cholangiography is the term for radiography of the bile ducts.
2.12 Laparoscopic Cholecystectomy
A transhepatic cholangiogram is performed by placing a needle through the liver and into the common bile duct so that a contrast medium can be injected. The term transhepatic literally means through or across the liver, indicating the path of the needle in this procedure.
When the gallbladder is removed, a T-shaped tube may be placed temporarily in the stump of the cystic duct to drain bile. This tube can also be used as a route for administration of a contrast agent to examine the biliary ducts radiographically. The procedure may be done as part of the surgical procedure or afterward if the tube is left in place. The examination is called a T-tube cholangiogram.
Treatment of gallstones may involve traditional surgery to remove the gallbladder, cholecystectomy, but more and more often, a laparoscope is used to remove the damaged gallbladder through a much smaller incision. This procedure (see illustration), called laparocholecystotomy—or laparoscopic cholecystectomy if the entire gallbladder is removed—has reduced recovery times significantly.
2.13 Lithotripsy
A less invasive treatment for gallstones, extracorporeal shock wave lithotripsy (ESWL), may be effective in some situations. The suffix -tripsy means surgical crushing. You will recall that you learned about this procedure and these terms with respect to treatment for kidney stones in a previous module.
2.14 Common Bile Duct Disorders
The combining form choledoch/o means common bile duct. An inflammation of the common bile duct, then, is called choledochitis, and the presence of a calculus in the common bile duct is called choledocholithiasis.
Blockage or suppression of bile flow, as caused by a stone in this illustration, is termed cholestasis. Cholestasis may have other causes and may occur in the hepatic ducts as well.
Sometimes, after a cholecystectomy, a temporary opening into the common bile duct is made through the abdominal wall for the purpose of drainage to prevent cholestasis while the swelling subsides. This surgical opening is called a choledochostomy. Surgical repair of the duct is choledochoplasty, and the surgical formation of a new opening between this duct and the duodenum is called a choledochoduodenostomy. The surgical incision of the common bile duct to remove a stone is called choledocholithotomy.
Module 11
Introduction
In this module, you will learn more about the medical terms associated with the urinary system. When you complete this module, you should be familiar with terms that describe the anatomy of that system and have a good understanding of terms that specify disorders affecting the urinary system. You will recognize terms for tests and procedures that are used to diagnose and treat urinary system disorders, and you'll learn about categories of drugs used to improve urinary function. As you work through this module, you may need to refer to the basics of word structure that were introduced in Module 1.
This integrated learning program is intended as a supplement to your text—not as a substitute. Be sure to keep your text available for ready reference.
Objectives
In this module, you will learn to:
- Identify the major structures of the urinary tract and their functions.
- Identify renal failure as the cause of uremia.
- Identify blood, glucose, ketones, protein, or large numbers of red cells or white cells as abnormal findings in a urine specimen.
- Describe the significance of genitourinary infections and their association with some sexually transmitted diseases.
- Write the meanings of the word parts associated with the urinary system and use them to build and analyze terms.
1.1 Threaded Case Study: Mr. Seagraves
To help us understand how the urinary system functions, let's meet Mr. Seagraves, who is visiting his physician, Dr. Polvak, to express some concerns about a possible urinary dysfunction. We'll consider his symptoms as we learn about urinary system anatomy and physiology.
1.2 Blood/Urine Flow through Urinary System (animation)
The main components of the urinary system are the kidneys, ureters, urinary bladder, and urethra.
The principal organs of the urinary system are the kidneys. You will recall that the combining forms meaning kidney are ren/o and nephr/o. The kidneys perform the work of filtration, the process of removing urea, potassium, creatinine, and other wastes and excess ions from the blood. Eventually, these wastes are eliminated from the body by way of the ureters, bladder, and urethra. The process of eliminating waste from the body is termed excretion.
Urea is a nitrogenous waste formed in the liver and carried in the bloodstream to the kidneys, where it, along with other wastes, becomes a component of urine.
The urine travels from the kidneys, down the ureters, into the bladder, and out of the body through the urethra.
The combining form urin/o means urine or urination, and ur/o means urine or urinary tract.
1.3 Kidney Function
n addition to filtering the blood and eliminating waste products, the kidneys contribute to the body's homeostasis by maintaining a good balance of essentials, such as water, salts, and acids, in the body fluids.
The kidneys work with the endocrine system as well, secreting substances needed at distant sites in the body. These substances include renin, erythropoietin, and prostaglandins.
Renin is an enzyme that stimulates the liver to regulate blood pressure by responding to conditions of low blood volume or low salt content. You will recall that erythropoietin is the enzyme that stimulates the production of red blood cells. Prostaglandins are fatty acid derivatives that have effects on many organs. They are involved in degrading insulin and metabolizing vitamin D.
1.4 Layers of the Kidney
The kidney is divided into two layers: the outer layer, called the cortex, and the inner layer, or medulla. The cortex cradles the nephrons, the filtering units of the kidney. The medulla, or inner layer, contains the collecting tubules that receive the urine from the nephrons.
Blood vessels and nerves enter and leave the kidney through the hilum, a concave notch in its medial surface. Waste products are carried to the kidney in the bloodstream via the renal artery.
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Your kidney is about the size of your fist and weighs between 4 and 6 ounces in the average-sized adult. Make a fist now to get an idea of the size of your own kidney. Compare the fists of two different-sized people in your class to get an idea of the variations in size. |
1.5 Blood Flow through Kidney (animation)
When blood flows into the kidney through the renal artery, it passes through smaller and smaller arteries in the cortex of the kidney. The smallest arteries, called arterioles, are so small that blood flow through them slows.
If the blood flow slows too much, the kidney's endocrine functions come into play. The kidneys secrete the hormone renin into the blood to stimulate contraction of the arterioles so that blood pressure is increased and the flow in the kidneys becomes normal again.
From the arterioles, the blood in the kidney passes through a tiny mass of even tinier blood vessels called capillaries. This small ball is called a glomerulus (glomerul/o). The cortex region of the kidney contains hundreds of thousands of these glomeruli, which open into the cortex's other main component—the functional nephrons.
Each glomerulus is surrounded by a cup-shaped structure with a thin double membrane called a Bowman's capsule. Together, each glomerulus with its companion Bowman's capsule forms a renal corpuscle.
Each Bowman's capsule is part of a microscopic nephron. Nephrons are the main functional units of the kidney. Nephrons make up the bulk of the kidney and do the bulk of its work, processing blood plasma and forming urine.
1.6 Filtration
As you can see in this illustration, each nephron is made up of the Bowman's capsule, the Loop of Henle, and the renal tubules, proximal and distal, located on either side of the Loop of Henle. The distal renal tubule empties into the collecting tubule.
Blood passing through the glomeruli is filtered. Because the walls of the capillaries are so thin, water, salts, sugar, urea, and other wastes can pass through them, leaving the bloodstream and entering the nephron by way of Bowman's capsule. Thus, it is in the renal corpuscle that substances are transferred from the blood in the glomerulus to the nephron; that is, from vessels of the circulatory system to tubules of the urinary system.
Larger substances like proteins and blood cells cannot filter through the walls of the glomerulus under normal circumstances and thus remain in the bloodstream to be used by the body.
1.7 Reabsorption
Being trapped in the Bowman's capsule isn't the last chance for these substances, however. You may remember that, along with urea and other waste products, some useful substances like water, salt, and sugar were also filtered from the blood. These materials have one more opportunity to be returned to the bloodstream.
As these wastes exit the Bowman's capsule by way of the proximal renal tubule, most of the water, all of the sugar, and some salts are returned to the bloodstream through the walls of the capillaries that surround each tubule.
The other wastes remain in the tubule fluid and are carried through the Loop of Henle. In this long portion of the nephron, some of the salts from the tubule fluid are reabsorbed before the fluid moves on into the distal convoluted tubule where water and more salts are reabsorbed. The fluid is then carried out of the nephron via the collecting tubule.
1.9 Collecting System
From the nephron units, the urine flows into the larger collecting tubules. These terminate in cup-shaped collecting regions called calyces, or calices.
Each calyx (or calix) collects urine and empties it into the renal pelvis, the central collecting region of the kidney. The pelvis then narrows, funneling the urine into the ureter.
1.10 Other Organs of the Urinary Tract
The ureters are the tubes that carry urine from the kidneys to the urinary bladder. The combining form that means ureter is ureter/o.
The urinary bladder is a flexible, collapsible bag in which urine accumulates. The combining forms that refer to the bladder are cyst/o and vesic/o. The ureters enter the bladder at the triangular area called the trigone, and the point at which each ureter attaches to the bladder is called the ureterovesical junction. Urine enters the bladder through the ureters and exits through the urethra.
The urethra is the tube that conveys urine from the bladder to the outside of the body. As the bladder fills and expands it puts pressure on the base of the urethra, creating the desire to urinate. The response to this urge is the release of urine from the bladder into the urethra.
The urethral sphincters are a series of small muscles shaped like rings that surround the urethra and provide voluntary control of urine flow. Terms for the process of expelling urine from the bladder are micturition, urination, and voiding.
1.11 Female vs. Male Urethra
Notice the difference in urethral structure between the male and female systems. In the female (Fig. A), the urethra is approximately 1.5 inches long, with a small meatus (the opening to the outside of the body) between the clitoris and the opening of the vagina.
The male urethra (Fig. B) is approximately 8 inches long, with the meatus at the tip of the penis. Notice that part of the urethra is embedded in the prostate gland. There are significant differences between male and female in both the structure and the function of the urethra. The principal functional difference is that, in the female, the urethra carries only urine from the body, but in the male, the urethra serves as an exit for both urine and semen.
1.12 Threaded Case Study: Mr. Seagraves
Remember Mr. Seagraves? He is having no apparent difficulties with urination, but he does have troublesome side pains. Dr. Polvak suspects, among other possibilities, that there could be a blockage in his urinary system, perhaps due to a stone. In fact, a stone in a ureter often causes flank (side) pain that later shifts to the lower back.
1.1 Threaded Case Study: Mr. Seagraves
You may remember that Mr. Seagraves' physician, Dr. Polvak, suspects, among other possibilities, that Mr. Seagraves may have a urinary blockage. Naturally, the presence of infection is one of the first things that should be either confirmed or ruled out. This is easy to determine when working with the urinary system, thanks to the multipurpose urine specimen.
1.2 Urinalysis
The most common test used to diagnose disorders of the urinary system is urinalysis (UA); that is, testing the urine for signs of pathologic conditions.
The first and easiest aspect of urinalysis is the visual assessment, an observation of the specimen's color and clarity.
Normal urine ranges in color from pale to deep yellow, depending on the amount of water it contains. Other substances, such as medications or pigments from certain foods, can affect its hue as well
1.3 Urine Clarity and Specific Gravity
The assessment of clarity is made after the urine has been gently mixed and placed in a urinalysis tube. Appearance of urine normally ranges from clear to slightly hazy. Degrees of haziness are reported as clear, slightly hazy, moderately hazy, markedly hazy, cloudy, or turbid. Haziness greater than slight may indicate the presence of an excessive amount of urine sediment.
Another test that is a part of urinalysis is the measurement of specific gravity (SG). The specific gravity is a reflection of the concentration of particles in the urine. Specific gravity is measured using a floating instrument called a hydrometer or urinometer. The specific gravity of water is 1.0, and the normal range for urine is 1.010 to 1.025. Abnormal elevation of specific gravity may be an indication of dehydration or of elevated protein content in the urine.
1.4 Urine Chemistry
The pH test is used to determine the urine's degree of acidity or alkalinity. Urine pH is normally acidic but may become alkaline in the presence of a bladder infection. This is because the bacterial breakdown of urea releases ammonia, which is very alkaline.
Analysis by means of reagent strips, illustrated here, permits quick determination of pH and also indicates the presence of a number of substances that have diagnostic significance. The substances being measured or analyzed are called analytes. They include albumin and other blood proteins, glucose, ketones, and blood.
The combining form ur/o, meaning urine, and the suffix –ia, meaning condition, are combined to form -uria, referring to a condition of urine or a substance present in urine.
Recall the combining form hemat/o means blood. Neither blood nor hemoglobin is normally found in urine. The abnormal condition of blood in the urine is called hematuria.
You will recall from Module 7 that albumin is an important protein in blood plasma. Its combining form is albumin/o. It helps maintain the water balance in tissues and transports small molecules in the blood. The presence of abnormal levels of albumin in urine is called albuminuria. Similarly, proteinuria is the presence of protein in urine, glycosuria is the presence of glucose, and ketonuria is the presence of ketones.
One of the earliest signs of renal involvement in diabetes mellitus is albuminuria. Glycosuria is another indication of diabetes mellitus.
1.5 More Urine Chemistry
Ketonuria is an indication that the body is burning fat for energy. Ketones, also called ketone bodies, are byproducts of fat metabolism. This condition can be an indication that diabetes mellitus is out of control. Ketoacidosis is the term for the presence of excess ketone bodies in the blood. This condition often precedes or accompanies ketonuria.
Phenylketonuria (PKU) is a very different condition from ketonuria, although the terms are related. PKU is a genetic disease characterized by an inability of the body to utilize the essential amino acid phenylalanine. This condition can cause severe mental retardation if not identified and treated at birth. Testing for PKU immediately after delivery is a routine procedure in hospital obstetrics departments.
By now you are familiar with bilirubin, the pigment that is released during hemolysis, the destruction of red blood cells. Bilirubin is another analyte that is assessed as part of a urinalysis. Normally there is no bilirubin in urine. Its presence indicates disease of the liver or bile ducts. The illustration shows amber-colored urine with yellow foam indicative of an elevated bilirubin level.
As mentioned previously, these analytes can be assessed quickly and easily using a multi-test reagent strip. Further diagnostic information is obtained by the microscopic examination of urine sediment. The urine is spun rapidly in a centrifuge to separate the liquid from the sediment.
1.6 Microbiology
The tests we have just discussed are evaluations of the physical and chemical properties of urine and are part of a routine urinalysis. Another aspect of urine assessment is the microbiological testing that is important when infection is suspected. You will recall that microbiology is the study of microorganisms. The common microbiology procedures used for diagnosis of urinary disorders are called culture and sensitivity. The two procedures are often ordered simultaneously, and the order is abbreviated C and S.
To identify specific pathogens in urine specimens, a culture is made. The urine is smeared with a sterile instrument onto a sterile culture medium, a plate containing an agar preparation that supports the growth of microorganisms. The plate is then covered and placed in an incubator at body temperature for 24 hours. Any significant growth of microorganisms is examined macroscopically and under a microscope to determine what pathogen is present. The accompanying illustration shows culture results from a patient with pyelonephritis.
When a culture is positive for the presence of infection, a sensitivity test may be performed. A second agar plate is smeared with organisms from the first plate, small paper disks containing various antibiotics are also placed in the plate, and it is incubated for 24 hours. Microorganisms that are sensitive to a particular antibiotic will not grow around a disk that contains it. This assessment helps to ensure that an effective antibiotic will be prescribed for treatment.
1.7 Blood Urea Nitrogen (BUN)
Laboratory analysis of blood specimens can provide important information about kidney function. When the kidneys are not functioning properly, waste products tend to accumulate in the blood and can be identified and measured there.
A blood urea nitrogen (BUN) test is a laboratory blood test used to determine how much nitrogen has accumulated in the blood in the form of urea, a waste product of protein metabolism. The term for excess urea in the blood is uremia.
A further measure of kidney function is a test of its ability to remove creatinine from the blood. Creatinine is a byproduct of protein metabolism that is normally filtered from the blood by the kidneys. The creatinine clearance test compares the creatinine concentration in a blood sample with the amount the patient excretes in urine over 24 hours.
1.9 Cystoscopy
A common diagnostic procedure is cystoscopy. In this procedure, a special type of endoscope, called a cystoscope, is inserted into the urinary meatus, through the urethra, and into the bladder.
Using light, lenses, and mirrors, the cystoscope reveals the bladder mucosa, which can be examined for tumors, calculi, or inflammation. A cystoscope can also be used to draw urine samples or inject contrast agents for radiography.
Cystoureteroscopy is somewhat more involved than cystoscopy because it includes examination of the ureters as well as the bladder.
1.10 KUB, MRI
The simplest radiographic study of the urinary tract is the examination called a KUB (Fig. A), which stands for kidneys, ureters, and bladder. This is a single plain-film image of the abdomen taken with the patient in the supine position. The term plain film refers to the fact that no contrast agent is used.
The magnetic resonance image, or MRI (Fig. B), demonstrates the kidneys in relation to other organs in the abdominal region. Magnetic resonance angiography (MRA) is useful in evaluating the renal blood supply.
1.11 Retrograde Urogram and Renal Scan
The retrograde urogram, also called a retrograde pyelogram, seen in the illustration on the left, is a radiographic examination of the kidneys and ureters in which a contrast medium is injected through ureteral catheters that are placed via cystoscope.
A renal scan, seen in the illustration on the right, is a radioisotope study that can reveal the presence of a renal embolus and other obstructions.
1.12 Intravenous Pyelogram (IVP)
The intravenous pyelogram (IVP), also called an intravenous urogram (IVU), involves injection of a contrast medium into a vein. The contrast agent travels to the kidneys and is filtered into the urine. Traditional x-rays show the contrast material filling the kidneys, ureters, and bladder, bringing cysts and other abnormalities into view. Another name for this test is the excretory urogram.
1.13 Cystography
Cystography uses a radiopaque contrast medium to visualize the bladder in special radiographs, or x-ray images, called cystograms.
The voiding cystourethrogram (VCUG), illustrated here, can also reveal abnormalities of the bladder. In this procedure, the bladder is filled with a contrast agent and radiographs are taken of the bladder and urethra as the patient expels urine.
1.14 Nephrosonography
Many renal conditions can be diagnosed using images made by high-frequency sound waves or ultrasound. The procedure of making ultrasound images of the kidneys is called nephrosonography. This term is formed by combining nephr/o with son/o, which means sound, and -graphy, which means recording.
1.15 CT Scan, MRI
The CT (computed tomography) scan (Fig. A) presents transverse x-ray images with or without the use of contrast media, but the use of a contrast agent is particularly helpful for studying the urinary system. This CT scan clearly identifies multiple cysts in the kidneys, seen on the image as rounded dark areas.
In MRI (magnetic resonance imaging), a cylinder-shaped machine produces images using a strong magnetic field and pulses of radio waves that capture the movement of protons within the body. An MRI image is seen in Figure B.
Small renal tumors are now found earlier than ever because of the increased use of the CT scan and MRI.
1.16 Renal Arteriogram
An adequate blood supply to the kidneys is essential to normal kidney function. One method of evaluating the renal blood supply is the radiographic study called a renal arteriogram, shown here. This image highlights the arteries of the left kidney.
Renal arteriography is performed under fluoroscopic control by introducing a catheter into the femoral artery and threading it through the aorta to the renal artery. Radiographic images are recorded during and immediately after the injection of a contrast medium through the catheter.
2.1 Urinary Tract Infections
The general term for any abnormal condition of the urinary tract is uropathy. Now we will learn about some of these conditions, beginning with those that are classed as inflammatory disorders.
Urinary tract infections (UTIs) may be classified as either upper UTIs or lower UTIs, depending on whether the primary site of infection is in the bladder or in one or both kidneys. Sometimes the exact site is difficult to pinpoint.
One of the most common UTI conditions is cystitis, inflammation of the bladder. The combining form cyst/o means bladder, and the suffix -itis refers to inflammation. Cystitis may be accompanied by a discharge (-rrhea), or cystorrhea. It can be caused or aggravated by the presence of a herniation (-cele) of the bladder wall called a cystocele.
Other terms using the combining form cyst/o include cystostomy, the surgical formation of a new opening from the bladder to the outside of the pelvic wall. Cystotomy is an incision into the bladder. Take care to distinguish between these similar terms.
A cystectomy is the surgical removal of the bladder. This procedure also necessitates a ureterostomy to provide a route for urine to exit the body.
2.2 Symptoms of Urinary Tract Infections
Urination difficulties are among the first signs of cystitis. The term dysuria means painful or difficult urination. The prefix dys- means difficult and ur/o means urine. The suffix -ia means condition.
One form of dysuria is polyuria, or frequent urination, signified by the prefix poly-, which means many or frequent. At the opposite end of the spectrum is oliguria, which means infrequent, or few urinations, or a scanty quantity of urine. The combining form olig/o means few or scanty. Anuria literally means lack of urination. The prefix a- means without. In practice, this term refers to a urinary output of less than 100 ml per day.
Other terms that refer to specific urinary symptoms include nocturia and nycturia, which both mean increased urination at night; noct/i and nyct/o both mean night.
Urinary retention refers to incomplete emptying of the bladder. Urinary incontinence refers to loss of bladder control. Urgency refers to the intense sensation of needing to urinate immediately. Retention, incontinence, and urgency are common symptoms of uropathy. Urgency, particularly, is a symptom of cystitis.
2.3 Lower UTIs
There are specific terms for inflammation of individual parts of the urinary tract. For example, the combining form urethr/o refers to the urethra; thus, urethritis is inflammation of the urethra. In fact, cystitis and urethritis are the two most common UTIs. Combining these terms creates cystourethritis, inflammation of the bladder and the urethra. This condition is also referred to as urethrocystitis.
2.4 Conditions and Treatments Involving the Urethra
The urethra is sometimes examined or diagnosed in connection with other structures besides the bladder. For instance, the combining form rect/o refers to the rectum; thus, something that is rectourethral pertains to both the rectum and the urethra. This can also be termed urethrorectal.
The structure of all words is not reversible, however. For instance, urethrovaginal has only one spelling order. The combining form vagin/o means vagina. Thus, urethrovaginal means pertaining to the urethra and the vagina.
Herniation of the urethra is represented by adding the suffix -cele, which means hernia, forming the word urethrocele. Other terms pertaining to the urethra include urethrospasm, which is, as you might easily guess, a spasm of the muscle tissue of the urethra. Urethrorrhea means a discharge from the urethra (-rrhea means flow or discharge). A surgical incision of the urethra is a urethrotomy.
Transurethral surgery is performed by inserting an instrument through the lumen of the urethra and/or through its wall. Recall that trans- means across or through.
2.5 Nephritis
The combining forms nephr/o and ren/o both refer to the kidney or its nephrons. Thus, anything that is toxic or destructive to kidney cells may be termed nephrotoxic. The combining form tox/o means poison.
Knowing that -itis is a suffix indicating infection or inflammation, then nephritis means inflammation of the kidney.
Acute interstitial nephritis is a particular type of inflammation that occurs in some patients in reaction to certain drugs. This condition causes poor renal function; there may also be fever, eosinophils in the blood and urine, and skin rash like that shown in the illustration. The best treatment is to discontinue the offending drug; corticosteroids may be prescribed to decrease the inflammation.
2.6 Renal Abscess
In the bacterial infection referred to as acute pyelonephritis, the renal pelvis and medulla are invaded by bacteria that produce numerous tiny abscesses, collections of pus. The term pyelonephritis comes from the combining forms pyel/o, meaning renal pelvis, and nephr/o, meaning kidney.
Inflammation of the renal pelvis alone would be identified by combining pyel/o with the suffix -itis to form pyelitis.
Glomerulonephritis is a kidney infection involving the glomeruli and nephrons, the filtration portions of the kidney. Although both pyelonephritis and glomerulonephritis cause hematuria and pain in the kidney regions, glomerulonephritis can be differentiated because it also causes proteinuria and decreased urinary output.
When urinalysis reveals the presence of pus, the condition is called pyuria. The combining form py/o means pus, ur/o means urine, and -ia refers to a condition; thus, pyuria is pus in the urine.
Abscesses can be revealed on radiographic images, like this CT scan.
2.7 Genitourinary Conditions
Urinary tract infections are particularly common in females. There, the proximity of the reproductive organs and anus makes it possible for bacteria from these areas to spread to organs of the urinary system via the urethra. The term genitourinary, or urogenital, is used to identify anything that pertains to both genital and urinary structures.
We have already encountered the suffix -rrhea, which means discharge or flow. The term gonorrhea is derived from the combining form gon/o, which means genitals or reproduction. Gonorrhea (as seen in the culture on the right) is a sexually transmitted disease (STD) caused by the gonococcus bacterium. Cocci are spherical bacteria. You can see some of these microorganisms in the gram stain shown in the illustration. Symptoms of gonorrhea are dysuria and urethritis in males and vaginitis, inflammation of the vagina, in females.
2.10 Kidney Stones
Kidney stones are also called nephroliths or renal calculi. The term renal is, of course, from the combining form ren/o, meaning kidney. The term nephrolithiasis refers to the condition of having a kidney stone; it comes from the combining forms nephr/o, also meaning kidney, and lith/o, meaning stone or calculus.
Renal calculi are thought to be formed by high levels of calcium or uric acid in the blood. They tend to block passageways in the ureter, the bladder, or renal pelvis.
The general term for the condition of calculi anywhere in the urinary tract is urolithiasis. The presence of a stone in the ureter is called ureterolithiasis.
If the stone creates a blockage, it can cause ureteritis, inflammation of the ureter, and hydronephrosis, an abnormal distention of the kidney with urine (hydr/o means water). If the obstruction occurs in the lower part of the ureter, urine will tend to accumulate proximal to the stone, resulting in hydroureter.
2.11 Ureterostomy
The surgical removal of a stone from the ureter is called ureterolithotomy. Formation of a new opening through which the ureter can be drained is a procedure called a ureterostomy (see illustration). A ureterectomy is the surgical removal of all or part of a ureter. When a ureterectomy is performed and the kidney is functioning, the procedure must be combined with a ureterostomy so that the urine can exit the body.
2.12 Threaded Case Study: Mr. Seagraves
Remember Mr. Seagraves? The side pains he has complained about are getting worse and are now occurring in his back. They are severe now, making him double over, pace, sweat profusely, and vomit. His most recent urinalysis showed hematuria. From these signs and symptoms, Dr. Polvak recognized the need to quickly confirm his earlier suspicion and take action. He ordered an IVP, which confirmed that Mr. Seagraves indeed has nephrolithiasis, the presence of kidney stones.
2.13 Lithotripsy
Sometimes drinking large amounts of fluid will promote the excretion of a stone, flushing it from the body. When this strategy does not succeed, the stone must be destroyed or removed.
Litholysis means destruction of a stone. Lith/o means stone and -lysis means destruction. Litholysis can sometimes be accomplished by administering medications that are excreted through the kidneys and have a chemical effect that dissolves the stone. This method is particularly effective when the stone is made up of uric acid deposits.
More often uroliths are treated by extracorporeal shock wave lithotripsy (ESWL), a shock wave administered from outside the body. The combining form lith/o refers to a stone or calculus; the suffix -tripsy means surgical crushing. Thus, extracorporeal shock wave lithotripsy is a noninvasive procedure that shatters or crushes the stones for easier, eventual passage from the body through the urethra.
With small stones, inserting a catheter and crushing the calculus with an instrument called a lithotrite may accomplish lithotripsy. The interior of the kidney is seen through a nephroscope.
2.14 Threaded Case Study: Nephrolithotomy
Mr. Seagraves is fortunate that lithotripsy is the type of treatment he needs. Some patients, however, need surgery.
One surgical option is a nephrolithotomy. The combining form nephr/o, as we have seen, means kidney; lith/o means stone; the suffix -tomy means incision or cutting. Thus, nephrolithotomy is a surgery to remove the stone by making an incision into the kidney. Removing the stone through an incision in the renal pelvis (pyel/o) is called pyelolithotomy. This is not to be confused with a pyelostomy, which uses the suffix -stomy to describe the formation of a new opening into the renal pelvis. Finally, pyeloplasty is the plastic repair of the renal pelvis.
2.15 Polycystic Kidney
Heredity can also play a part in kidney disease. One hereditary disorder, called polycystic kidney disease, is a condition in which multiple (poly-) fluid-filled sacs, or cysts (cyst/o), form both inside and outside the kidney. The word cystic can refer to a fluid-filled sac or a cyst or growth.
Polycystic disease is progressive. It usually shows no symptoms until adulthood. When it begins to manifest itself, hematuria is one of the early symptoms.
Other signs of polycystic disease include urinary tract infections, hypertension, and uremia, an accumulation of toxins in the blood. You will recall that the suffix -emia means a condition of blood. Uremia occurs when the kidneys stop functioning properly.
Polycystic kidney disease causes nephromegaly, enlargement of the kidney.
Another term heard in relation to polycystic disease is nephrolysis. This term combines nephr/o with the suffix -lysis, which means the process of destroying. The term nephrolysis is used in two different ways; it can mean the destruction of kidney tissue, such as that which occurs with polycystic disease, or the surgical procedure of freeing a kidney from adhesions.
2.16 Renal Cell Carcinoma
Blood in the urine can signal a number of disorders; one of the more serious is renal cell carcinoma, a cancerous tumor of the kidney. The seriousness and survival rate of this tumor is determined by the extent to which it spreads. It often metastasizes (spreads) to the bone and the lungs.
2.17 Bladder Carcinoma
Although many disorders of the urinary system involve the kidney, the bladder (cyst/o) is actually a more common site of malignancy, particularly in men, smokers, and individuals over the age of 50. Chemicals used by some kinds of industrial workers can also contribute to risk.
This illustration shows carcinoma of the urinary bladder. Early symptoms usually include hematuria, polyuria, and dysuria.
2.20 Renal Failure
Renal failure is just what its name indicates: the kidneys fail to excrete urine. This condition may be acute or chronic.
Acute kidney failure may result from interference with the renal blood supply, blockage of the renal collecting system or ureter, or problems with the kidney itself that prevent proper filtration of blood or production of urine.
The two most common causes of chronic renal failure are hypertension and diabetes mellitus. Other causes include damage to the kidney caused by infection, atherosclerosis, or polycystic kidney disease.
Renal failure is primarily evaluated by means of laboratory blood tests, particularly the blood urea nitrogen (BUN) and creatinine clearance tests. The creatinine clearance test is particularly sensitive for this purpose.
The severity of renal failure can vary from mild to life threatening. The final phase of the chronic version of this disorder is end-stage renal disease (ESRD), which can be fatal. Treatment consists of hemodialysis (HD), peritoneal dialysis (PD), or renal transplant.
2.21 Dialysis
When the kidneys can no longer function to remove waste materials from the bloodstream, dialysis can save a patient's life. There are two kinds of dialysis. Hemodialysis (HD) (Fig. A) is the use of an artificial kidney machine. The combining form hem/o means blood, dia- means through, and -lysis means process of destroying. Thus, hemodialysis is the process of removing toxins by diffusing blood through a semipermeable membrane.
The other method is peritoneal dialysis (PD) (Fig. B), which involves the introduction of a catheter and a special solution into the peritoneum. The wastes pass into the fluid from the bloodstream and are then drained from the body.
In more severe cases, a renal transplant may be needed. In this procedure, the patient receives a kidney from a suitable donor after it is surgically removed from the donor.
The combining form nephr/o is combined with the suffix -ectomy to create the term nephrectomy, which means surgical excision of a kidney. Thus, the surgical removal of both the diseased kidney and the donor kidney is called a nephrectomy.
2.22 Renal Hypertension
Renal hypertension, also called renovascular hypertension, is one of several disorders that is closely linked to kidney function. You will recall that the term hypertension means high blood pressure. Renal hypertension is a form of secondary hypertension (hypertension caused by another condition in the body). It occurs in less than 5% of all people with high blood pressure.
In this disease, narrowing of the renal artery reduces blood flow to the kidney. The stenosis is often related to atherosclerosis but can also result from injury to the artery that produces scarring. Reduced blood flow to the kidney leads to an excessive release of the hormone renin, a potent hormone that increases blood pressure.
2.23 Diabetes Insipidus
There are two distinctly different types of diabetes: diabetes insipidus (DI) and diabetes mellitus (DM). Both are related to the function of the urinary system.
Diabetes insipidus is induced by disorders of the kidneys or the pituitary gland. This condition leads to polyuria and polydipsia. You will recall that these terms mean frequent urination and excessive thirst, respectively.
DI causes glucose to be excreted in the urine, but blood glucose levels remain normal. Treatment of DI depends on the cause. When lack of certain pituitary secretions is the problem, it is treated with the administration of antidiuretic hormone (vasopressin). When kidney function is at fault, the condition is said to be nephrogenic, that is, originating in the kidneys. In this case, it is treated with anti-inflammatory drugs.
2.24 Diabetes Mellitus
You will recall from Module 10 that diabetes mellitus (DM) is a disease in which the body does not make enough insulin or cannot use normal amounts of insulin properly. Insulin is a hormone that regulates the amount of sugar in the blood. A high blood sugar level can cause problems in many parts of the body. Diabetes mellitus is similar to diabetes insipidus in that DM also causes polyuria and polydipsia.
With diabetes mellitus, the small blood vessels in the body become injured. When the blood vessels in the kidneys are damaged, the kidneys cannot filter the blood properly. The body then tends to retain more water and salt than it should, resulting in weight gain and ankle swelling. Proteinuria is a sign of these diabetic complications. When the condition is severe, waste products build up in the blood, causing uremia.
DM may also result in damage to nerves, causing difficulty in emptying the bladder. The pressure from an over-full bladder can cause urine to back up and injure the kidneys. Also, when urine remains in the bladder for a long time, cystitis (bladder infection) is likely due to the rapid growth of bacteria in urine that has a high glucose content.
2.25 Nephrotic Syndrome
When excessive amounts of protein are filtered into the urine, the patient may experience swelling and susceptibility to infection. This condition is known as nephrotic syndrome, which is not a disease, but is rather a sign of a disease that damages the glomeruli so that they do not filter proteins properly. This occurrence is sometimes referred to as "leaky glomeruli."
Generalized edema and rapid weight gain are characteristic features of this condition. Blood tests show hypoalbuminemia (an abnormally low level of albumin in the blood), and urinalysis reveals albuminuria and proteinuria.
Often, the cause of nephrotic syndrome is unknown, but sometimes it appears to be related to allergic reactions to medications, to infections such as hepatitis B, or to diabetes mellitus. A biopsy of kidney tissue is sometimes helpful in identifying the cause and deciding on the appropriate treatment.
Introduction
In this module, you will learn about the medical terms associated with the reproductive systems, both male and female. When you complete this module, you should be familiar with terms that describe the anatomy of these systems and have a good understanding of terms that specify disorders affecting the reproductive systems. You will recognize terms for tests and procedures that are used to diagnose and treat reproductive system disorders, and you'll learn about categories of drugs used to treat these conditions. As you work through this module, you may need to refer to the basics of word structure that were introduced in Module 1.
Remember that this integrated learning program intended as a supplement to your text—not as a substitute. Be sure to keep your text available for ready reference.
Objectives
In this module, you will learn to:
- Identify and match the structures and functions of the male and female reproductive systems.
- Name the three types of uterine tissue.
- Write the meanings of the word parts and use them to build and analyze terms.
- Write the meanings of the abbreviations.
1.1 Threaded Case Study: Grace
From the previous modules, we've begun to see how each body system makes a unique contribution to our overall health and interacts with other systems to maintain our body's integrated functioning. In this module, we'll consider the male and female reproductive systems and how their structures equip them for their contributions to the fascinating story of human reproduction. Then in the module that follows, we will look at the reproduction process.
Before we begin our look at the female reproductive system, let's meet Grace. Grace and her mother have come to see their family physician, Dr. Thomas, because Grace needs a routine checkup and a health certificate for camp. Grace is 12 years old and is beginning to feel very grown up. Together with Grace, we will learn some terms and facts about the female reproductive system.
1.2 Female Reproductive Organs
The word genitalia is used to refer to all organs of reproduction, either male or female, both within the body and external to it. It is represented in the combining form genit/o.
More specifically, the female reproductive system is represented by the combining form gynec/o, which means female. Thus, gynecology is the study of the female reproductive system and its diseases.
The structure of the female reproductive system enables it to support a variety of activities. Its primary organs, or gonads, are the ovaries (sing., ovary). Their counterparts in the male, as you'll see, are the testes (sing., testis). The ovaries produce the female sex cell, the ovum (pl., ova). The ovum and the male sex cell, the spermatozoon (pl., spermatozoa), are both called gametes.
The combining forms used to represent the ovary are oophor/o and ovari/o. For instance, the word ovarian means pertaining to the ovary. The combining form for the egg or ovum is o/o. The formation of ova is called oogenesis, using the combining form o/o and the suffix -genesis, which means producing or beginning.
In addition to oogenesis, the ovaries secrete hormones that help to control the reproductive cycle. We will discuss these chemical messengers and their effects on the reproductive cycle in the lesson that follows.
1.3 Female Reproductive Functions
The female reproductive system functions to receive the sperm during sexual intercourse, which is called coitus. The sperm then unites with the ovum, and this process is called conception or fertilization.
Supporting the development of the fertilized ovum and providing nutrients to the newborn are functions of other reproductive organs in the female. These processes are discussed in the module that follows.
1.4 Ovaries
The ovaries and other organs of the female reproductive system are located in the pelvic cavity. The ovaries are paired, almond-shaped organs that form part of the internal genitalia.
Each ovary weighs about 3 grams and has a puckered, uneven appearance due to its composition. It is made up of thousands of small sacs called graafian follicles that contain the ova.
1.5 The Uterus
The ovaries are connected to another major reproductive organ, the uterus, by bands of fibrous tissues called utero-ovarian ligaments.
The uterus is a small, but very strong, pear-shaped organ that lies between the urinary bladder and the rectum, normally tilting forward and slightly upward. It consists of two main components: a wide upper portion, called the body, or corpus, and a narrow lower neck, called the cervix or cervix uteri. The body of the uterus rounds into an upper prominence known as the fundus.
The combining forms used to represent the uterus are hyster/o, metr/o, and uter/o. For example, the word uterine means pertaining to the uterus. Metritis is the term for inflammation of the uterus, and hysterectomy means excision of the uterus.
The combining form that refers to the cervix is cervic/o.
1.6 Uterine Walls (animation)
The walls of the uterus are composed of three layers: the endometrium, an inner lining of mucous membrane; the myometrium, a thick, muscular middle layer; and the perimetrium, or uterine serosa, an external membranous layer.
As you have learned, the combining form metr/o, meaning uterus, forms the basis of these terms. You should recognize the prefixes endo-, meaning within, and peri-, meaning around. Recall that my/o means muscle, and the suffix -ium means membrane.
The uterine walls enclose a small cavity that is capable of expanding greatly during pregnancy. In addition to its role during pregnancy, the uterus is involved in the reproductive processes of menstruation and labor.
1.7 Fallopian Tubes
The fallopian tubes, also called uterine tubes, are paired ducts extending from the uterus over the top of each ovary and opening into the abdominal cavity. The combining form for the uterine tube is salping/o.
The ovum is expelled from the ovary by means of the process known as ovulation. Then the fringelike projections on the outer end of each tube, called fimbriae, catch the ovum, bringing it into the tube and moving it toward the uterus. The fallopian tubes also serve as passageways for sperm cells as they move toward the ovaries.
If fertilization takes place, the fertilized ovum will lodge, or implant, in the highly vascular uterine wall. If fertilization does not occur, the uterine lining is discarded during menstruation. The processes of fertilization and implantation are discussed in Module 13.
1.8 The Vagina
The vagina is the organ into which sperm are deposited and through which the infant emerges at birth. It is an expandable muscular canal 3 to 4 inches in length that lies between the urinary bladder and the rectum. The vagina extends from the uterine cervix to the outside of the body. Sometimes the vaginal opening is covered by a fold of mucous membrane called the hymen.
The vagina is represented by the combining forms colp/o and vagin/o. For example, the word vaginal is an adjective that refers to the vagina, and a colposcope is an instrument for examining the vagina.
1.9 External Female Genitalia
The region between the vaginal orifice and the anus is called the perineum. Its combining form is perine/o. The perineum forms the floor of the pelvic cavity.
The external structures of the female reproductive system are located between the superior rim of the pubic bones and the perineum. Together, they are known as the vulva, represented by the combining form vulv/o. For example, the words vulvar and vulval both mean pertaining to the vulva. A number of structures compose the vulva.
The mons pubis is a pad of fatty tissue that overlies the symphysis pubis, the joint between the two pubic bones.
Between the mons pubis and the perineum lies the vestibule, the area that contains the urethral and vaginal orifices. It is bounded on both sides by folds of tissue called the labia. The origin of this term means lips.
The labia majora are the outer folds of fatty tissue on each side of the vestibule. The smaller labia minora are the inner folds of mucous membrane.
At the point where the labia minora come together anteriorly is the clitoris, a small, rounded organ of sensitive erectile tissue that serves as a receptor of sexual stimulation.
The labia minora contain sebaceous (oil-producing) glands, Skene's glands, and Bartholin's glands. The two Bartholin's glands are located on either side of the vaginal entrance and secrete lubricating mucus during sexual arousal.
2.1 Menarche
At birth, the ovaries of a female child contain about 1 million ovarian follicles, each enclosing an ooblast, or embryonic ovum (Fig. A). You may recall that the combining form o/o means ovum; the suffix -blast means embryonic or early form.
As the girl reaches puberty, the stage at which the ability to reproduce begins, the number of ooblasts will have reduced to about 400,000. With puberty comes menarche, the first occurrence of menstruation, the periodic (usually monthly) bloody discharge from the shedding of the endometrium from the nonpregnant uterus. The combining form men/o, which forms a number of terms related to menstruation, means month.
When menstruation is completed, the monthly menstrual cycle, or uterine cycle, continues as the endometrial lining of the uterus begins to thicken once again in preparation for a possible pregnancy.
Over the course of a woman's reproductive life only about 400 to 500 ooblasts will develop to become mature ova (Fig. B) before menopause, the time in a woman's life when menstruation and ovulation cease.
2.2 Threaded Case Study: Grace
Dr. Thomas notes that Grace's breasts have begun to swell and declares that puberty has arrived. She tells Grace that her ovaries have begun to produce estrogen and she will soon begin to menstruate. Dr. Thomas uses charts with pictures to help Grace understand the menstrual cycle and the wonderful changes that are occurring in her body.
2.3 Ovulation (animation)
Let's take a closer look at how this reproductive cycle works.
Throughout a woman's reproductive lifetime, her body repeatedly prepares itself for conception. Each month, one or more of the ovarian follicles matures and ruptures, releasing a developed ovum in the process called ovulation.
The ruptured follicle, because of its fatty content, develops a golden appearance, earning it the name corpus luteum, meaning yellow body. If fertilization does not occur, the corpus luteum becomes nonfunctional and disappears.
2.5 Ovaries Secrete Estrogen
As we noted earlier, the ovaries, in addition to their primary role in oogenesis, also perform another very important function—hormone secretion.
Follicular cells surround the ovum within the ovarian follicles and secrete the hormone estrogen.
Our knowledge about the influences of estrogen continues to grow. Some of the hormone's actions include promoting the development of reproductive organs and secondary sex characteristics and initiating the menstrual cycle.
2.6 Other Female Hormones
Another hormone, progesterone, is secreted by the corpus luteum, which also produces a small amount of estrogen. Progesterone stimulates growth of the endometrial lining of the uterus to support the fertilized ovum should pregnancy occur.
Production of both estrogen and progesterone is controlled by two pituitary gland hormones. Follicle-stimulating hormone (FSH) induces the development of ovarian follicles and their secretion of estrogen.
Luteinizing hormone (LH) causes the mature follicle to rupture and to release its ovum. LH also stimulates the formation of the corpus luteum.
Sustained high blood levels of estrogen and progesterone occur during pregnancy and with the use of contraceptive birth control pills, suppressing ovulation.
2.7 Menstrual Cycle (slide show)
Cyclic changes involving the uterus occur simultaneously with the events of the monthly ovarian cycle. Let's become more familiar with these changes by looking at the process of menstruation.
Menstruation occurs each month in which an ovum is not fertilized. The changes in the uterus—the regrowth, proliferation, and shedding of its endometrial lining—typically take place over a period of about 28 days.
During the first 5 days of the menstrual cycle, patches of dead cells from the endometrium slough off, causing arteries that supplied the tissue to tear. During menstruation, a secretion consisting of tissue debris and blood from the torn arteries is discharged from the uterus through the vagina.
Following menstruation, from days 6 through 13 of the cycle, the cells of the uterine lining reproduce and the endometrium undergoes a period of repair. At the same time, another ovarian follicle containing a maturing ovum is developing, and FSH (follicle-stimulating hormone) is causing estrogen production to increase toward its peak level.
As the estrogen content in the blood increases, the anterior pituitary gland is stimulated to secrete LH (luteinizing hormone), causing the mature follicle to eject the ovum. Ovulation often occurs on day 14 in a 28-day reproductive cycle.
As the ovum moves through the fallopian tube for possible fertilization, the uterine lining again begins to prepare for pregnancy. LH triggers the corpus luteum to secrete an increased level of progesterone and, in response, the uterine lining becomes thicker and develops a greater blood supply. When fertilization does not occur, secretions from the corpus luteum diminish. This drop in the level of progesterone causes constriction of the blood vessels supplying the endometrium. Consequently, endometrial cells die and the reproductive cycle begins again with the onset of menstrual bleeding.
2.8 Menopause
Unlike other body systems, the female reproductive system has a limited period during which it engages in its primary function. Thirty to 40 years after menarche, a woman's reproductive life comes to a close during what is known as menopause or the climacteric. This alteration in reproductive function is characterized by a decrease in estrogen production. Ovulation and menstruation gradually become less frequent and eventually cease.
3.1 Gynecologic Examination
When Grace is older, her routine doctor visits will include gynecologic examinations. A gynecologic examination covers all the basics of any physical examination of the female reproductive system. It includes examination of the breasts, external genitalia, and the pelvis. The internal structures of the vagina and cervix are examined using an instrument called a speculum, which opens the vaginal orifice.
During this examination, the gynecologist takes several specimens. Some will be cultured to detect certain kinds of infections. One specimen will be used for a Pap smear, also called a Papanicolaou smear or test. This microscopic examination of shed cells from the vagina and cervix aids in early detection of cancer of the cervix.
3.2 Examination of the Female Reproductive Organs
Another instrument used to examine the vagina and cervix is called a colposcope (Fig. A). This low-powered microscope magnifies the mucosa, making is possible to discern tissue that shows evidence of dysplasia, abnormal tissue development.
You will recall that the combining form colp/o means vagina. Adding the suffix -itis yields the term colpitis, meaning inflammation of the vagina. The more common term for this is vaginitis; vulvovaginitis is inflammation of both the vagina and the vulva.
Recall that -dynia means pain and -rrhagia means hemorrhage. Therefore, colpodynia is pain in the vagina, and colporrhagia is hemorrhage from the vagina.
If a suspicious cervical or vaginal lesion is seen during colposcopy, a cervical or endometrial biopsy may be needed to collect tissue for further examination.
An instrument used to examine structures within the abdominopelvic cavity, including the reproductive organs, through an incision into the abdominal wall is called a laparoscope (Fig. B). The procedure is called laparoscopy.
3.3 Candidiasis
A common type of vulvovaginitis is candidiasis. The lay term for this condition is yeast infection. It is caused by the yeast-type fungus Candida albicans. Candida is part of the normal flora of mucous membranes that are in contact with the outside of the body. This organism is normally kept in check by bacteria that also inhabit the same areas. When bacteria have been killed by antibiotics or when the immune system is suppressed by drugs or disease, candidiasis often results.
Candida organisms are also called monilia, and candidiasis is therefore also called moniliasis.
3.4 Ovarian Disorders
Pain in an ovary is called oophoralgia. Recall that oophor/o refers to the ovary and –algia means pain.
A condition originating in the ovary is said to be oophorogenous. If the condition is an inflammation (-itis), it will be called oophoritis. If the inflammation includes the uterine tube (salping/o) as well, the diagnosis will be oophorosalpingitis. Inflammation of the uterine tube alone is called salpingitis.
3.5 Leiomyomas
Fibroids, the most commonly occurring pelvic tumors, are benign growths that consist of smooth muscle and fibrous connective tissue. Fibroids are also called leiomyomas. This term is composed of lei/o, meaning smooth, and my/o, signifying muscle. The combining form leiomy/o refers specifically to smooth muscle, the type found in organs other than the heart. You are familiar with the suffix -oma, which means growth or tumor.
The cause of fibroids is unknown, but their development is believed to be stimulated by estrogen. Fibroids are often asymptomatic, even though they can grow to be quite large. If symptoms are present, they may include menorrhagia, general enlargement of the lower abdomen, pressure on organs near the fibroid, and pain if the stalk on which the tumor is growing becomes twisted. Depending on their location, fibroids can also interfere with fertility.
Fibroids are often diagnosed during a pelvic examination with the finding of an enlarged and distorted uterus. The diagnosis may be confirmed by use of a variety of imaging techniques, including radiography and sonography.
3.6 Hysterosalpingography
Hysterosalpingography is a diagnostic examination that involves radiographic imaging of the uterus and fallopian tubes following the injection of a contrast medium.
This test demonstrates the internal contours of the uterus and demonstrates occlusion of fallopian tubes. It is frequently used to investigate possible causes of infertility. The accompanying hysterosalpingogram shows a large fibroid occupying the entire uterine cavity as noted by the arrowheads.
3.7 Hysteroscopy
A biopsy of a fibroid can be done through hysteroscopy, a procedure in which a fiber-optic instrument called a hysteroscope is passed through the vagina and into the uterus. This procedure is also useful for the excision of cervical polyps. You may recall from Module 9 that polyps are small tumors that arise from mucous membranes.
3.8 Endometriosis
Pelvic discomfort and abnormal bleeding may be related to a disorder of the endometrium, the tissue that lines the uterus.
For example, endometritis is inflammation of the endometrium, and endometriosis is the growth of endometrial tissue outside the uterus, usually within the pelvic cavity (the different sites of endometriosis are demonstrated in the illustration). Problems arise with endometriosis because this tissue, while not contained within the uterus, still responds to hormonal changes and goes through the cyclic changes of bleeding and proliferation.
3.10 Dysplasia
Cancer of the uterus usually begins with certain cell changes called dysplasia. The term for this kind of abnormality comes from combining the prefix dys-, meaning bad or abnormal, and the suffix -plasia, meaning development or formation.
3.11 Cervical Cancer Therapies
The cervix is an area of concern with respect to cancer. When malignant lesions are discovered early enough, excision can eliminate the lesion and may also prevent the spread of cancer to nearby organs.
Three other methods of treatment include radiation therapy, cautery, and cryotherapy.
Cautery, seen in the illustration, is the searing or destruction of tissue using either heat or caustic chemicals. This is accomplished either by the application of a substance such as nitric acid or by the use of an electrically charged platinum wire (electrocautery).
With cryotherapy, on the other hand, abnormal tissue is destroyed with extremely cold temperatures, such as the application of liquid nitrogen. The term comes from combining cry/o, which means cold, and -therapy, which means treatment. Cryotherapy is also called cryosurgery.
3.12 Hysterectomy
In some cases, more extensive surgery is required. For instance, when tumors in the uterus become widespread, even if the tumors are benign, hysterectomy (Fig. A) may be recommended. The combining form hyster/o means uterus, and -ectomy means surgical removal. Thus, the term hysterectomy refers to the surgical excision of the entire uterus.
When removal of the uterus is done through the vagina (colp/o), this procedure is called colpohysterectomy (Fig. B). If it takes place through an incision in the abdominal wall (lapar/o), the procedure is called a laparohysterectomy.
3.13 Surgical Procedures
Sometimes the ovaries (oophor/o) are removed (-ectomy) along with the uterus (hyster/o). This procedure is called an oophorohysterectomy (seen in illustration).
Removal of just the ovary is called, as you might expect, an oophorectomy; when the uterine tube (salping/o) and ovary are removed, the term is salpingo-oophorectomy or the less common oophorosalpingectomy.
3.14 Additional Surgical Procedures
Some procedures have more than one name. For instance, when vaginal cancer requires the removal of part or all of the vagina, the procedure may be called either colpectomy or vaginectomy. Removal of all or part of the vulva is called vulvectomy (seen in the illustration). In all three terms, we encounter the familiar suffix -ectomy, meaning removal. You'll recall that the combining forms colp/o and vagin/o both mean vagina and vulv/o refers to the vulva.
3.15 Dilation and Curettage (D&C)
Sometimes the physician may decide to scrape material from the endometrium, the lining of the uterus, in order to assess disease, correct heavy vaginal bleeding, or remove residue of the placenta after birth. This procedure is called dilation and curettage (D&C). In this procedure, the cervix is dilated to allow the insertion of a curette into the uterus. This scoop or spoon is used to scrape and remove material from the endometrium.
3.16 Menstrual Disorders
Menstruation may be either normal or profuse, both of which are indicated by the same term—menorrhea. This term is made by combining men/o (month) with -rrhea (flow; discharge).
To avoid confusion between normal and abnormal menstrual flow, it is common to refer to the normal monthly flow of blood from the genital tract by calling it menstruation or menses.
Profuse menstruation can be identified by combining men/o with the suffix -rrhagia, which means hemorrhage, to create the term menorrhagia. Amenorrhea is the absence of menstruation, and dysmenorrhea is painful or difficult menstruation.
Premenstrual syndrome (PMS) is a set of disconcerting symptoms that affects many females during the week before their menstrual periods. Characteristic symptoms are both physical and emotional, including headache, fluid retention, fatigue, weight gain, anxiety, depression, and irritability.
Metrorrhagia is irregular or prolonged uterine bleeding, not directly related to menstruation.
1.1 Threaded Case Study: Martin
In this lesson, we'll consider how certain anatomic structures of the male body help to accomplish the task of human reproduction.
As we learn about the male reproductive system, we will get acquainted with Martin. On a recent visit to his physician, Dr. Spalding, Martin told him about problems he had been having with urination—urgency, frequency, and difficulty starting his urination.
In addition, Martin reported that, very occasionally, he has seen blood in his semen. Soon we will see how Dr. Spalding identifies the cause of Martin's symptoms. For now, let's focus on the organs and structures of the male reproductive system.
1.2 Male Reproductive Organs
The male reproductive system includes both internal and external structures. Gonads are the organs, male or female, that produce the reproductive cells. As we have seen, the female gonads are the ovaries; in the male, they are the testes, also called testicles.
Four combining forms represent the testes: orchi/o, orchid/o, test/o, and testicul/o. For example, the word testicular means pertaining to a testicle. Most diagnostic and surgical terms, however, are formed using either orchi/o or orchid/o.
Testis is the singular form of testes. The testis is an essential structure of the male reproductive system because it is within this organ that sperm are produced. The testes are small, smooth, oval-shaped, paired glands.
Before birth these glands descend from their position in the abdominal cavity into the scrotum, a cutaneous pouch suspended between the thighs in a diamond-shaped area called the perineum.
1.3 Spermatogenesis
Each testis is divided into 200 or more cone-shaped lobules that contain tiny coiled tubes, known as the seminiferous tubules.
The combining form that means sperm is spermat/o. Thus, spermatogenesis is the production and development of sperm cells. This process occurs along the lining of the tubules. An absence of sperm production is called aspermatogenesis.
A sperm in embryonic form is a spermatoblast, and a cell that will become a mature, functioning sperm is called a spermatocyte.
Because the seminiferous tubules perform the essential work of the testes, they comprise the functional, or parenchymal, tissue of the organ, directly producing sperm.
The tubules are surrounded by Leydig cells, which produce the major male sex hormone testosterone.
1.4 Epididymis
Eventually, the spermatozoa are released into the lumina (sing., lumen; channels or passageways) of the seminiferous tubules. From there they are transported through a system of small ducts into the epididymis, represented by the combining form epididym/o.
The epididymis is one of a pair of comma-shaped, tightly coiled tubes in which sperm cells continue to mature until they are either ejaculated through the urethra or disintegrate and are reabsorbed by the body.
1.5 Vas Deferens
The epididymis runs down the length of the testis, then turns upward and tapers into an inferior tail portion that is continuous with the vas deferens, also known as the ductus deferens. The combining form for this tubular structure is vas/o. You will recall that this word part also refers to any vessel or duct.
The vas deferens, encased in the spermatic cord, extends into the abdominal cavity. Each vas deferens then enters the base of the prostate gland (prostat/o) to join with the seminal vesicle and form the ejaculatory duct. Ejaculation is the expulsion of semen from the urethra.
In a vasectomy, the vas deferens is surgically closed off for the purpose of sterilization. Analyzing the semen for the presence of sperm is a way to evaluate the effectiveness of this procedure.
1.6 Seminal Vesicles and Ejaculatory Ducts
The seminal vesicles are two saclike structures that lie between the bladder and the rectum. These glands secrete a thick, yellowish substance that serves to nourish the sperm and, together with other reproductive organ secretions, form seminal fluid, or semen (semin/o).
The ejaculatory ducts are short tubes that extend from the seminal vesicles, through the prostate, to the urethra. The vas deferens joins with the ejaculatory duct within the prostate gland, as seen in this illustration, and this is where the sperm become combined with the semen.
1.8 Prostate Gland
The prostate gland lies under the bladder near the rectal wall. It is a doughnut-shaped organ, about the size of a chestnut, that encircles the upper portion of the urethra. The prostate gland secretes an acid substance that becomes a part of the seminal fluid and serves to liquefy coagulated semen.
1.9 Bulbourethral Glands (Cowper's Glands)
The Cowper's glands, also called bulbourethral glands, are two round, pea-sized structures that lie just below the prostate gland. Like the seminal vesicles and the prostate gland, the bulbourethral glands secrete a fluid that becomes part of the semen, helping to transport sperm and contribute to the survival of the male sex cells.
1.10 Penis
The penis is the external male reproductive organ, consisting of a root, the body or corpus, and the tip, which is called the glans penis. It functions as the organ of copulation and of urinary excretion. The term penile means pertaining to the penis.
The penis contains the urethra, which serves as a passageway both for semen during ejaculation and for urinary elimination. Its structure consists of three cylindrical masses of erectile tissue; one mass surrounds the urethra and the outermost mass is covered with skin.
An overlap of erectile tissue at the tip of the organ forms the slightly bulging structure called the glans penis. In the center of the glans penis is the urethral opening. The combining form meaning glans penis is balan/o.
The prepuce, or foreskin, is the loose-fitting, retractable casing of the glans penis. The removal of the prepuce is a surgical procedure known as circumcision. This term combines circum-, meaning around, and cis/o, meaning to cut.
2.1 Threaded Case Study: Phimosis
Let's return now to Martin, who is still having problems with both urination and occasional blood-tinged semen. In addition, he reports some pain in his lower back and genital area and some new symptoms—occasional painful ejaculation and recurring bladder infections. Dr. Spalding examines Martin's abdomen and pelvis for tenderness and then examines the structure of the penis.
The penis may be affected by structural abnormalities. For example, one of the first things Dr. Spalding checks for is phimosis, a structural disorder in which the prepuce, or foreskin, fits so tightly over the glans penis that it cannot retract. This condition can obstruct the flow of urine and can lead to development of infection because of the accumulation of secretions under the foreskin. Phimosis is treated by circumcision.
Fortunately, Martin does not have phimosis.
2.2 Cryptorchidism
Another structural disorder of the male reproductive system is failure of the testes to descend from the abdomen. The testicles normally descend from the abdominal cavity into the scrotal sac before birth. When one or both of the testes fails to descend, the condition is known as cryptorchidism.
Cryptorchidism is the most common congenital testicular condition. If the testes fail to descend spontaneously by the time a child is 2 years old, he may be a candidate for hormonal injections to encourage descent or an orchiopexy is performed. This surgical procedure is used to mobilize the testes and attach them within the scrotum to prevent their retraction. Suturing of the testes is called orchidorrhaphy. If cryptorchidism is not corrected before puberty, it becomes a risk factor for infertility and testicular cancer.
2.3 Hydrocele
A hydrocele is an accumulation of fluid in any saclike cavity or duct, but the term is most commonly applied to a fluid accumulation in the scrotum. In infants it is caused by an open passageway between the abdomen and the scrotum. This occurs when the passage fails to close after the testicle descends. In adults it may be caused by inflammation of the testis or epididymis, an inguinal hernia, or interference with lymphatic drainage.
Diagnosis of the condition is made by ultrasound examination and by transillumination—shining a powerful light through the scrotal tissue to identify the fluid-filled mass. Generally, hydroceles are treated by aspiration of the collected fluid using a needle and syringe. The treatment for persistent hydrocele is a surgical procedure known as hydrocelectomy.
2.4 Inflammatory Conditions of the Male Reproductive System
The term urogenital means pertaining to both the urinary system and the reproductive system. These systems share certain anatomical structures in the male.
A routine part of any urogenital examination will include inspection of the external genitalia and a urinalysis.
This illustration shows the terms for inflammation of various structures of the male urogenital tract and provides examples of organisms that are commonly associated with infections of each. The definitions of these terms are as follows:
balanitis: inflammation of the glans penis
urethritis: inflammation of the urethra
prostatitis: inflammation of the prostate
cystitis: inflammation of the urinary bladder
epididymitis: inflammation of the epididymis
orchitis: inflammation of the testis
Some of these infections, such as gonorrhea and genital herpes, are transmitted sexually. They will be discussed further in Module 13.
2.5 Threaded Case Study: Testicular Carcinoma
Next, Dr. Spalding checked for the possibility of testicular carcinoma, although this condition was unlikely because it accounts for less than 1% of all forms of cancer in men. It occurs most frequently in the 15- to 35-year-old age group, but is more common in those who have had undescended testicles. As expected, Martin is not diagnosed with testicular cancer.
2.7 Threaded Case Study: Digital Rectal Exam
Martin's physician has ruled out obstructions and disorders of the penis, urethra, or bladder. Now he turns his attention to the prostate gland as a possible cause of Martin's symptoms.
Prostatic cancer is the most common cancer in men. It is a slow-growing tumor that affects an increasing proportion of men after the age of 50. Detection of the disorder is accomplished by digital rectal examination (DRE), finger palpation of the prostate gland through the rectum.
In addition to this exam, a test called the PSA assay can also help identify prostate cancer by checking for elevated levels of PSA in the blood. PSA stands for prostatic specific antigen (or prostate-specific antigen), a protein produced by the prostate and elevated in patients with cancer.
Methods of treating prostate cancer include radiation therapy; prostatectomy, surgical excision of the prostate gland; and hormonal chemotherapy. Hormonal chemotherapy works by decreasing the androgens (male hormones) that prostatic cells depend on to grow.
2.9 Benign Prostatic Hyperplasia
Martin's PSA levels are somewhat elevated, but this does not necessarily mean that Martin has prostate cancer.
PSA assay does not detect cancer only; elevated PSA levels can also be an indication of other disorders of the prostate, including benign prostatic hyperplasia (BPH), a noncancerous condition that is common in men over 50, characterized by enlargement of portions of the prostate gland, as seen in the illustration.
Because the urethra passes through the prostate gland, enlargement of the prostate can compress the urethra and obstruct urinary flow. Symptoms include a decrease in the urinary stream, urgency, hematuria, urinary retention, and cystitis due to incomplete emptying of the bladder. These symptoms should be familiar to you because they were introduced and explained in Module 11.
2.10 Prostate Surgical Procedures
BPH may be treated surgically by transurethral prostatic resection (TURP). During this procedure, a resectoscope—an instrument used to excise prostatic tissue—is inserted through the urethra and portions of the gland are removed (see illustration).
When there is less prostatic enlargement, an alternative surgical intervention called transurethral incision of the prostate (TUIP) may be used. In this procedure, the urethra is widened by means of small incisions in the bladder neck and prostate gland.
Recently, nonsurgical methods of treating BPH have become available. For instance, in transurethral microwave thermotherapy (TUMT), heat capable of eliminating excess prostatic tissue is delivered to a designated area.
Transurethral needle ablation (TUNA) uses low-level radiofrequency energy to eliminate excess cells. In addition, a variety of medications have been approved for the relief of BPH symptoms.
2.11 Threaded Case Study: Prostatitis
Dr. Spalding has conducted a thorough physical assessment, including the digital rectal examination, during which he was able to collect a fluid sample from the prostate gland.
Tests confirm that Martin does not have BPH or prostate cancer. A laboratory analysis of the fluid shows white blood cells, indicating inflammation but no infectious bacteria. His urinalysis also shows the presence of white blood cells.
Eventually Dr. Spalding is able to diagnose that Martin has chronic nonbacterial prostatitis, which you will recall means inflammation of the prostate gland.
2.12 Threaded Case Study: Martin
Because Martin does not have a sexually transmitted disease (STD), a potential cause of prostatitis, Dr. Spalding explains that this condition may instead be caused by anxiety and stress, by a reduction in usual sexual activity, or by starting and stopping the flow of urine rather than relaxing the bladder and pelvic muscles throughout urination. In addition, heavy lifting with a full bladder can also cause urine to back up and seep into the prostate, causing inflammation. Finally, Dr. Spalding explains that even such recreational activities as bicycling and jogging may sometimes cause prostatitis.
Even though Martin's inflammation is not caused by an infection, low doses of antibiotic may improve his symptoms. He is also given a drug called an alpha blocker to help relax his prostate gland and bladder to improve urine flow. An over-the-counter pain reliever is recommended as well. If these don't help, Dr. Spalding may refer Martin to a physical therapist for pelvic exercises and heat therapy.
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