医护英语(diseases+and+disorders)(text+a&b)

Passage One Human Diseases
In this passage you will learn:
●disease and pathology
●the classification of diseases
●germs’ invasion of the human body
●the body’s defense agai nst invasion
●the body’s immunity to diseases
The brief survey of the human body in Chapter One has given us a glimpse into two different studies that are considered the fundamentals of medical sciences, namely anatomy and physiology. However, the picture is not complete without considering pathology, the science that deals with the structural and functional changes produced by the disease. In fact, the modern approach to the study of disorder emphasizes the close relationship of the pathological and physiological aspects and the need to understand the fundamentals of each in treating any body diseases.
Then what is a disease? It may be defined as a condition that impairs the proper function of the body or of one of its parts. Every living thing, both plants and animals, can succumb to disease. People, for example, are often infected by tiny bacteria, but bacteria, in turn, can be infected by even more minute viruses.
Hundreds of different diseases exist. Each has its own particular set of symptoms and signs, clues that enable a physician to diagnose the problem. A symptom is something a patient can detect, such as fever, bleeding, or pain. A sign is something a doctor can detect, such as a swollen blood vessel or an enlarged internal body organ.
Diseases can be classified differently. For instance, an epidemic disease is one that strikes many persons in a community. When it strikes the same region year after year it is an endemic disease. An acute disease has a quick onset and runs a short course. An acute heart attack, for example, often hits without warning and can be quickly fatal. A chronic disease has a slow onset and runs a sometimes years-long course. The gradual onset and long course of rheumatic fever makes it a chronic ailment. Between the acute and chronic, another type is called subacute.
Diseases can also be classified by their causative agents. For instance, an infectious, or communicable, disease is the one that can be passed between persons such as by means of airborne droplets from a cough or sneeze. Tiny organisms such as bacteria and fungi can produce infectious diseases. So can viruses. So can tiny worms. Whatever the causative agent might be, it survives in the person it infects and is passed on to another. Sometimes, a disease-producing organism gets into a person who shows no symptoms of the disease. The asymptomatic carrier can then pass the disease on to someone else without even knowing he has it.
Noninfectious diseases are caused by malfunctions of the body. These include organ or tissue degeneration, erratic cell growth, and faulty blood formation and flow. Also included are disturbances of the stomach and intestine, the endocrine system, and the urinary and reproductive systems. Some diseases can be caused by diet deficiencies, lapses in the body’s defense system, or a poorly operating nervous system.
Disability and illnesses can also be provoked by psychological and social factors. These ailments include drug addiction, obesity, malnutrition, and pollution-caused health problems.
Furthermore, a thousand or more inheritable birth defects result from alternations in gene patterns. Since tiny genes are responsible for producing the many chemicals needed by the body, missing or improperly operating genes can seriously impair health. Genetic disorders that affect
body chemistry are called inborn errors of metabolism. Some forms of mental retardation are hereditary.
How Germs Invade the Body
Humans live in a world where many other living things compete for food and places to breed. The pathogenic organisms, or pathogens, often broadly called germs, that cause many diseases are able to invade the human body and use its cells and fluids for their own needs. Ordinarily, the b ody’s defense system can ward off these invaders.
Pathogenic organisms can enter the body in various ways. Some—such as those that cause the common cold, pneumonia, and tuberculosis—are breathed in. Others—such as those that cause venereal diseases—enter through sexual contact of human bodies. Still others—such as those that cause hepatitis, colitis, cholera, and typhoid fever—get in the body through contaminated food, water or utensils.
Insects can spread disease by acting as vectors, or carriers. Flies can carry germs from human waste or other tainted materials to food and beverages. Germs may also enter the body through the bite of a mosquito, louse, or other insect vector.
How the Body Fights Disease
As a first line of defense, a healthy body has a number of physical barriers against infection. The skin and mucous membranes covering the body or lining its openings offer considerable resistance to invasion by bacteria and other infectious organisms. If these physical barriers are injured or burned, infection resistance drops. In minor cases, only boils or pimples may develop. In major cases, however, large areas of the body might become infected.
Breathing passages are especially vulnerable to infection. Fortunately, they are lined with mucus-secreting cells that trap tiny organisms and dust particles. Also, minute hairs called cilia line the breathing passages, wave like a field of wheat, and gently sweep matter out of the respiratory tract. In addition, foreign matter in the breathing passages can often be ejected by nose blowing, coughing, sneezing, and throat clearing. Unfortunately, repeated infection, smoking and other causes can damage the respiratory passageways and make them more susceptible to infection.
Many potential invaders cannot stand body temperature (98.6℉or 37℃). Even those that thrive at that temperature may be destroyed when the body assumes higher, fever temperatures.
Wax in the outer ear canals and tears from eye ducts can slow the growth of some bacteria. And stomach acid can destroy certain swallowed germs.
The body’s second line of defense is in the blood and lymph. Certain white blood cells flock to infected areas and try to localize the infection by forming pus-filled abscesses. Unless the abscess breaks and allows the pus to drain, the infection is likely to spread. When this happens, the infection is first blocked by local lymph glands. For example, an infection in the hand travels up the arm, producing red streaks and swollen, tender lymph glands in the armpit. Unless the infection is brought under control, it will result in blood poisoning.
Phagocytes are located at various sites to minimize infection. One type in the spleen and liver keeps the blood clean. Others in such high-risk areas as the walls of the bronchi and the intestines remove certain bacteria and shattered cells.
How We Become Immune to Disease
The body has a special way of handling infection. It has a system that fends off the first traces of an infectious substance and then, through a “memory,” gives the body a long-lasting immunity against future attacks by the same kind of invader.
Many substances could harm the body if they ever entered it. These substances, or antigens, range from bacteria and pollen to a transplanted organ (viewed by the body as an invader). To fight them the body makes special chemicals known as antibodies.
Antibodies are a class of proteins called immunoglobulins. Each antibody is made of a heavy chain of chemical subunits, or amino acids, and a light chain of them. The light chain has special sites where the amino acids can link with their complements on the antigen molecule. When an antibody hooks up with an antigen, it often puts the antigen out of action by inactivating or covering a key portion of the harmful substance. In some cases, through the process of opsonization, antibodies “butter” the surface of some antigens and make them “tastier” to phagocytes, which engulf the antigens. Sometimes an antibody hooks to a bacterial antigen but needs an intermediate, or complement, to actually destroy the bacterium. As the antibody-antigen complex circulates in the blood, the complex “f ix es” complement to it. In turn, the complement causes powerful enzymes to eat through the bacterial cell wall and make the organism burst.
There are several kinds of immunoglobulin s—IgM, the largest; IgG, the most plentiful and versatile; and IgA, the next most plentiful and specially adapted to work in areas where body secretions could damage other antibodies. Other immunoglobulins are tied in with allergic reactions. IgM is made at the first signs of an antigen. It is later supplanted by the more effective IgG.
When infection first strikes, the immunity system does not seem to be working. During the first day or so, antibodies against the infection cannot be found in the blood. But this is only because the basic cells involved in antibody production have been triggered by the presence of antigen to multiply themselves. The antibody level starts to rise on about the second day of infection and then zooms upward. By the fifth day the antibody level has risen a thousandfold. The first antibodies, the large IgM type, are not the best qualified to fight a wide range of antigens, but they are particularly effective against bacteria. The more versatile IgG is circulating in the blood on about the fourth day of infection. Its production is stimulated by the rising level of IgM in the blood. At this time, IgM production drops off and the immunity system concentrates on making IgG. The IgG type of antibody sticks well to antigens and eventually covers them so that the antigens can no longer stimulate the immune response and IgG production is switched off. This is an example of negative feedback control.
Passage Two Diagnosis and Prognosis
In this passage, you will learn:
●diagnosis and its process
●typical contents of a medical history
●physical examination as a component of diagnosis
●laboratory test as a component of diagnosis
●importance of prognosis
Diagnosis
In most clinical encounters, the patient presents basic questions to the doctor: What’s wrong with me? What is causing my illness ? These questions set the stage for making a diagnosis, i. e. determine the cause of an illness and a diagnosis is accomplished with history, physical examination and laboratory testing.
The process of diagnosing a disease begins with the person’s health history. Th e physician asks the patient questions on both present and past illnesses, family history of disease, habits and so on. The following table presents typical contents of a standard medical history.
Description of patient
Age, gender, race, occupation and parity (for woman).
Chief complaint
Four or five words, preferably quoting the patient, stating the purpose of the visit and the duration of the complaint. Occasionally the patient states a request instead of a complaint such as I need a flu shot.
Other physicians involved in the patient’s care
Name, address, telephone number, and relationship to the patient.
History of the present illness
For each major symptom, what, where, when, how much, chronological course, what makes the symptom better or worse, past medical care, questions to narrow diagnostic possibilities.
Past medical history
Previous illnesses and hospitalizations, immunizations, medications the patient takes, allergies,, and alcohol, tobacco, and drug habits.
Social and occupational history
Description of a typical day in the patient’s life and how the present illness affects it, social supports (family, friends, and colleagues) available to the patient, and occupational history.
Family history
History of genetically related di seases in the patient’s family and longevity and cause of death of family members.
Review of systems
Systematic review of major organ systems: skin, hematopoietic system (including lymph nodes), head, eyes, ears, nose, mouth, throat, neck, breasts, and respiratory, cardiovascular, gastrointestinal, genitourinary, musculoskeletal, nervous, endocrine and psychiatric systems.
Asking the patient’s medical history is followed by the general physical examination which includes measuring height and weight, and taking blood pressure; listening to the heart and lungs with a stethoscope; and examining eyes, ears, and mouth. Tests of hearing and vision are sometimes performed in routine physical examinations. Reflex tests are simple tests of nerve conduction that involve, among several other tests, tapping with a rubber hammer in areas such as the knee.
Since body fluids often reveal important information about the nature of the disorder, laboratory testing plays an important role in determining the patient’s disea se. Blood tests can determine whether the person has anemia—that is, an insufficient amount of healthy red blood cells—infection, or a blood disease, such as leukemia. Blood analysis can also uncover nutritional deficiencies and other disorders. The glucose-tolerance test, which is used to diagnose diabetes, measures insulin activity by monitoring the level of glucose, or sugar, in the blood.。

Urine is also tested for glucose as well as for bacteria, protein, and other materials. Glucose in the urine is sometimes caused by diabetes. Bacteria in the urine can indicate a kidney or bladder infection, and the presence of protein may result from a kidney disorder. A stool sample is tested for disease-causing microorganisms and for blood, which is often a symptom of intestinal disease.
Spinal fluid is examined for microorganisms and other unusual contents when a nervous system disorder is suspected. Mucus from the nose and throat can be tested to identify the organisms responsible for respiratory infections.
A sample of tissue can be taken from an organ or any other part of the body by a process called biopsy. The tissue is then sliced into very thin sections, stained with special dyes, and studied under the microscope to discover abnormalities in the cells.
Radiographs, or X-ray photographs, are used to examine various parts of the body. A chest X ray, for example, can help diagnose tumors, pneumonia, and tuberculosis. X rays can also show bone fractures and other conditions of the musculoskeletal system.
Radiopaque liquids are injected into the urinary tract, spinal column, circulatory system, and other areas. These materials do not allow X rays to pass through them. Thus they allow X-ray examination of soft tissues that would otherwise be invisible by X ray. Spinal cord disorders, for example, often show up in myelograms after a radiopaque liquid has been injected into the spinal canal. V arious kinds of angiograms show heart and circulatory disease. In these procedures a radiopaque dye is injected into a vein or artery, X-ray photographs will then show if there is a blockage or an aneurysm.
X-ray examination of the esophagus and stomach is carried out by having the patient swallow a radiopaque solution to highlight details in the upper gastrointestinal tract. For X raying the lower intestinal tract, the patient is given an enema.
CT (computed tomography) scanners are specialized X-ray cameras that take highly detailed images of hard and soft tissues. By picturing one layer of the body’s tissues a t a time, CT scanners can detect very small tumors and other disorders.
Nuclear magnetic resonance, or magnetic resonance imaging, is a hazard-free, non-invasive method that uses radio waves in the presence of a strong magnetic field to probe a patient and generate visual images of thin slices of the brain, heart, liver, and other organs. The high-contrast, variable-toned images that result can uncover tumors, blood-starved tissues, and plaques.
In the procedure termed scintigraphy, a small amount of a radioactive isotope is introduced into the body. A scintiscan camera, or gamma camera, measures the uptake and concentration of the isotope in certain tissues, such as the brain, kidney, or thyroid gland. Metabolic diseases and other disorders can be uncovered by this technique.
Ultrasonography is useful in locating tumors of the lung and abdominal cavity. It employs
ultra high frequency sound waves to form television images of internal organs. Because it produces no radiation, ultrasound is sometimes used during pregnancy to determine the size and position of the fetus.
Both the heart muscle and the nervous system produce electrical impulses that can be measured with special machines. The electrocardiograph (ECG) is useful for diagnosing certain h eart conditions. With electrodes taped to a person’s chest, the electrical activity of the heart can be recorded while the patient is either resting or performing some activity, such as walking on a treadmill. The electroencephalogram (EEG) measures the electrical activity of the brain through electrodes attached to the head. This test detects whether there is an area of irritability in the brain, such as occurs in epilepsy. The electromyogram (EMG) records the activity of nerves in muscles. The EMG is helpful in diagnosing degenerative nerve disorders such as multiple sclerosis.
Tests of pulmonary function measure the breathing capacity of the lungs and airways. By exhaling into a tube connected to a machine called a spirometer, information is obtained on respiratory functions.
Fiber optic technology has allowed physicians to see parts of the body that previously could be seen only by performing surgery. Fiber optic tools are essentially hair-thin glass fibers that can enter small areas and can be moved deep into the body cavities. Fiber optic technology can be used to examine the colon and the bronchial tubes in the lung.
A pelvic examination is performed to assess the general reproductive health of a woman. The Pap smear is a test for cancer of the cervix. A breast examination can detect lumps that may indicate cancer. Mammography, a procedure that involves using special X rays to produce an image of the soft tissues of the breast, is a much more reliable way to detect tumors.
Skin tests are used to diagnose hypersensitivity conditions, or allergies. Psychological tests are used to diagnose learning and mental disorders.
A physician may encounter another type of questions, such as: “Do you think I can get recovered from my condition? Can you help me to stay well?” The patient is asking their prognosis, the forecast of the probable results of his/her disease. In fact, for a great many patients, the prognosis is their biggest concern.
So, it is important to tell the patient the diagnosis and discuss what to expect from the clinical course of the condition. If the illness is likely to resolve without sequelae, reassurance is often all that is needed. However, the most difficult prognoses to discuss are those for fatal illnesses, especially many cancers. Most patients want to know even bad prognoses, but how much a physician tells a given patient should be determined primarily by the patient, not the physician. The physician has the duty to make the patient aware of his/her willingness to discuss the prognosis. Often detailed discussions are best conducted at follow-up visits, after the two have had a chance to get to know each other. The best physicians blend honest fact and hope together, helping the patient through the complicated steps of shock, denial, depression, and acceptance of fatal illness. Most importantly, they make it clear that they will not abandon the patient.。