SEXUALLY TRANSMITTED DISEASES (Part 1 of 2)   Leave a comment

1981: AIDS diagnosed. A new fatal, infectious disease was diagnosed in 1981. Called Acquired Immunodeficiency Syndrome (AIDS), it began appearing in major cities among homosexual men and intravenous drug users. Other high-risk groups were haemophiliacs and other recipients of blood or blood products, babies born of AIDS-infected women, bisexual men, and prostitutes and their customers. AIDS was soon recognized as a worldwide health emergency: a fatal disease with no known cure that quickly became an epidemic. It was especially widespread in Africa, the apparent land of its origin.

By 1983 the virus that causes the disease had been isolated. Some medicines, notably AZT (azidothymidine), slowed the disease’s progress for a few months or more; but the spread of AIDS continued relentlessly, with more than 3,000 new cases being reported each month by 1991.

The federal government had committed more than 1.6 billion dollars to research, while the homosexual community and other special interest groups sought more federal funding and greater assistance from the health insurance industry. Educational programs on safe sexual practices, such as the use of condoms, seemed the best means of slowing the epidemic. Meanwhile, more than 70,000 persons in the United States had died from AIDS by the end of the decade.

1981: AIDS identified. A strange, new, and deadly disease made its appearance in 1980. Physicians in such large cities as Los Angeles, New York, and San Francisco noticed that homosexual men were dying from rare lung infections or from a cancer known as Kaposi’s sarcoma. By 1981 the disease was identified and given a name: AIDS, or acquired immunodeficiency syndrome.

The virus that causes AIDS, human immunodeficiency virus (HIV), was identified by Dr. Luc Montagnier of the Pasteur Institute in Paris in research done during the years 1981-84. The results of Dr. Montagnier’s studies were released in 1984. Since its discovery, AIDS has become one of the world’s major health problems. Within certain populations it has become an epidemic: male homosexuals, haemophiliacs, and intravenous drug users in the United States, for example, and heterosexual men and women in Sub-Saharan Africa. Many people were infected through blood transfusions before HIV screening was introduced. An individual infected with the virus may not show the symptoms of AIDS for several years, but the condition is eventually fatal.

The search for a successful vaccine was pursued in laboratories around the world, with no success by the early 1990s. Meanwhile, the disease continued to spread to different parts of the world. Already rife in the United States, Europe, and sub-Saharan Africa by the mid-1980s, it quickly spread to Central and East Asia. The disease also began to spread to larger portions of the heterosexual community throughout the world.

Dec. 1, 1993: AIDS awareness day. The sixth annual World AIDS Day was celebrated in many countries. The commemoration was started in 1988 by the World Health Organization. The day was partly a memorial for those who had died from AIDS (acquired immunodeficiency syndrome). Although the growth of the epidemic had peaked in the United States in the early 1990s, the disease was still spreading rapidly in Africa and parts of Asia. No cure had yet been found, nor was there a successful vaccine to protect against contracting the disease.

Dec. 1, 1993: AIDS awareness day. The sixth annual World AIDS Day was celebrated in many countries. The commemoration was started in 1988 by the World Health Organization. The day was partly a memorial for those who had died from AIDS. Although the growth of the epidemic had peaked in the United States in the early 1990s, the disease was still spreading rapidly in Africa and parts of Asia. No cure had yet been found, nor was there a successful vaccine to protect against contracting the disease.

April 7, 1994: Failure of AZT. A team of British and French medical researchers reported that AZT, a drug often used to fight AIDS, does not slow the onset of the disease in persons who have the HIV virus. Published in the journal Lancet as the Concorde Report, the document stated that AZT does prolong the lives of patients who have developed AIDS, but it does not impede the progression of HIV into full-blown AIDS. The report was based on tests conducted on HIV-infected patients in Ireland, France, and the United Kingdom.

Diseases that can be passed between people during sexual contact have plagued humankind throughout history. Until recently such a disease was called venereal disease, or VD. The preferred term now is sexually transmitted disease, or STD. The two main venereal diseases in the United States have traditionally been gonorrhoea and syphilis. Scientists now know that many other diseases can be passed during sex. More than 30 STDs have been identified.

AIDS (acquired immunodeficiency syndrome), incurable disease caused by a virus that damages the human body’s immune system; believed to be transmitted through sexual contacts, blood transfusions, or contaminated needles used for intravenous drug injections; often fatal; high percentage of victims are homosexuals or drug abusers.

The names of such STDs as acquired immunodeficiency syndrome (AIDS) and gonorrhoea are known to most people; however, other STDs such as trichomoniasis and genital candidiasis may not be as familiar. Some STDs affect only a few people or do not cause life-threatening problems. Other STDs, such as gonorrhoea and chlamydial infections, affect many people or cause severe health damage.

STDs are a major health problem throughout the world. In the United States STDs strike an estimated 20 million people each year, or an average of one person every 1.5 seconds. About one half of STD patients are under the age of 25. Nearly 2.5 million teenagers are infected with an STD each year.

Pelvic inflammatory disease (PID), general, acute inflammation of the pelvic cavity in women.

Sterility, in biology, the inability to produce offspring; one cause is the production of non functioning sex cells.

The health problems caused by STDs seem endless. The diseases can cause arthritis, sterility, nervous system damage, heart disease, and death. Women and infants suffer the most damage from STDs. For example, each year more than 1 million women suffer from pelvic inflammatory disease resulting from gonorrhoeal or chlamydial infections. About 200,000 of these women become sterile each year. More than 300,000 babies are injured or die each year from STDs.


Mucous membrane (or mucosa), membrane that secretes mucus and lines the mouth, nose, throat, windpipe, lungs, eyelids, and the alimentary canal.

STDs are caused by a variety of organisms that include bacteria, protozoa, viruses, and very small insects such as Phthirus pubis, or pubic lice. These organisms usually live in the warm and moist parts of the body called mucous membranes. The penis, vagina, rectum, mouth, and eyes have mucous membranes. These organisms usually invade a person through the mucous membranes during sexual contact. Some STDs are passed by deep kissing or skin-to-skin contact, though these transmission methods are not common.

Anyone can get an STD regardless of age, sex, race, social class, or whether the person is heterosexual, homosexual, or bisexual. Exposure to STD organisms results from participating in certain sexual or drug-use behaviours

People with many sexual partners have the greatest risk of contracting an STD. The risk increases with each new partner. The risk is even greater if any of the partners have several sex partners.

It is virtually impossible to get an STD from such things as door knobs, toilet seats, drinking glasses, or whirlpool baths. Light and air destroy STD organisms very quickly. Some STDs such as gonorrhoea, syphilis, and genital herpes are practically always spread by sexual contact. Such diseases as AIDS, hepatitis, and pediculosis pubis, however, can sometimes be acquired through non-sexual means. AIDS and some forms of hepatitis can be acquired from infected blood in intravenous drug needles and syringes. Pubic lice can be picked up from contaminated clothing or bedding that is infected with the lice or their eggs.

Most STDs can also be passed during pregnancy or birth from an infected woman to her baby. Women can develop some infections in the vagina without having sex. It is possible but not common for those infections to be passed to others during sex. Other vaginal infections are sexually transmitted, but the woman’s sex partners may not have symptoms.


Most people have heard some information about STDs. In recent years public awareness has increased. The media have developed greater coverage of STDs, and more schools teach about STDs. There are news items on television and in newspapers and magazines about AIDS almost daily. This increased discussion has alerted people to how widespread STDs are, to STD health dangers, and to methods of preventing STDs. Hence, many people have become more cautious.

Medical personnel and public health officials believe that education is the key to controlling the spread of STDs. STDs are dangerous. Further medical advances may bring improved modes of treatment, but avoiding infection in the first place is vital. The actions of individual persons are the most important factors in halting the spread of these diseases. Many health educators emphasize the idea that the wisest teaching approach is to motivate people to practice responsible STD-preventive behaviour, such as sexual abstinence and sexual fidelity.

Communication between partners. Among people who are mature enough to have a sexual relationship, one of the most important things to do is communicate. A person should feel free to discuss concerns about getting an STD. The conversation can be started by one partner stating that he or she cares about the health and well-being of both persons. Persons deciding to have sex with a new partner should discuss ways of protecting each other.


SEXUALLY TRANSMITTED DISEASES (Part 2 of 2)   2 comments

Sexual precautions. Naturally, the most certain way to avoid an STD is to avoid sexual contact with infected persons. One sure way to do that is by sexual abstinence, meaning not having sex with anyone. Sexual abstinence in young adults is a normal and healthy choice.

The next most certain way of avoiding an STD is by practising sexual fidelity. It is nearly impossible for two people having a long-term, faithful relationship to get an STD. This is true unless one partner is infected at the start of the relationship or uses intravenous drugs and shares needles or syringes. Moreover, it is not always possible to know whether one’s partner is sexually faithful.

Condom (or rubber), device to prevent conception and disease.

Persons having sex outside a long-term, sexually faithful relationship should avoid exposure to certain body fluids. This suggestion also applies to those who are not sure whether their partner is infected with an STD. The person should not allow blood, semen, or vaginal secretions to touch the genitals, mouth, or anus. The proper use of latex condoms is one good way to prevent body fluids from entering one’s body. Although condoms made of animal membranes may protect against some STDs, they do not always protect against viral STDs, such as AIDS and herpes. Hence, the latex condom, or rubber, should be used. The latex condom, which is designed to protect both sexes, should be used during sex. The latex condom can greatly reduce the chances of getting an STD, though it is not 100-percent effective.

Using a contraceptive foam, cream, or jelly along with a latex condom may also help prevent STDs. Spermicides containing nonoxynol-9, which can kill most bacteria and viruses, are recommended. Other birth-control methods, such as birth control pills, do not provide protection from STDs.


Persons having sex should be alert for the symptoms of STDs. This is especially true for those having sex with a person other than a long-term, faithful partner. Any unusual or unexplained changes in the health of persons who engage in sex with different partners may indicate an STD. Of course, the changes may be caused by other diseases. STD symptoms may appear anywhere on the body, but usually they occur in the genital area. The major STD symptoms are: (1) genital discharge, (2) abdominal pain, (3) pain during urination, (4) skin changes, and (5) genital itching. Symptoms of infection with the AIDS virus include fatigue, fever, loss of appetite, weight loss, diarrhoea, night sweats, and swollen lymph glands.

Some STDs do not produce any symptoms until the disease is advanced. Often the symptoms are hidden, especially in females. For some STDs, the symptoms disappear without treatment, but the infection persists. All STDs, however, can be passed when the symptoms are not present. Persons suspecting that they have an STD should stop having sex, go to a doctor, and encourage their partners to go to a doctor. There may be no permanent health damage if the STD is treated early.


Persons who think they might have an STD should not try to diagnose or treat themselves. Only a doctor or other trained health professional can do those things. STD treatment is available from STD clinics in health departments, private doctors, family-planning clinics, and hospitals. A person can call the local health department to learn where STD treatment is given in his or her city. In every state, minors can get STD treatment without parental consent. Services are confidential. No one will know that a person has been to a clinic or a doctor unless the person tells others. If money is a problem, a person should still seek proper treatment. Most clinics will treat people without charge or for a small fee.

When seeing a doctor, the person should inform the physician why an STD is suspected. An STD examination is not the same as a routine check-up Special tests are performed to find out if the person has an STD. Usually a small sample of blood is taken from the patient’s arm. Also, fluid is often taken from the genitals or other exposed areas with a cotton-tipped swab.

Sometimes a doctor can tell right away if a person has an STD. Otherwise the doctor must wait for several days before the test results are known. Treatment, however, may begin on the first visit. Except for AIDS, genital herpes, and viral hepatitis, most STDs can be cured easily and quickly. Not all STDs are treated in the same way. Prescription drugs, shots, or creams may be used. The drugs or medicine should be taken exactly as directed by the doctor. A person should never take someone else’s medicine. Serious side effects could occur and the infection could be covered up but not cured.

Persons with an STD should be sure that their partners receive medical care so they do not become seriously ill. Also, treatment of the partner will keep the person from getting reinfected if sex with that partner resumes. One of the best ways to be sure a partner gets treatment is to take the person to the doctor or health department and to do so without delay. The partner can be told in person or over the phone that he or she might be infected with a sexually transmitted disease. A doctor or STD case specialist can help notify a partner confidentially.

Advances in Research

Despite the advances of medical science, the accurate diagnosis and effective treatment of a few STDs continue to remain serious problems. Much current STD research centres on these two areas, as well as on attempts to develop STD vaccines. Some progress has been made in these areas. For example, chlamydial infections, which have been difficult to diagnose, can be discovered more rapidly with a recently developed test. Also, a more effective treatment for genital herpes has been found. Even though herpes is not cured, these new medicines can relieve pain, shorten the time of blisters, and decrease the number of outbreaks of blisters. Scientists have also developed safer and improved treatment for genital warts.

In recent years, types of gonorrhoea that cannot be cured with penicillin or other antibiotics have emerged. This has greatly concerned public-health officials, who fear that the new strains could become widespread. However, scientists have been able to discover alternative drugs to treat the newer strains.

AIDS (acquired immunodeficiency syndrome), incurable disease caused by a virus that damages the human body’s immune system; believed to be transmitted through sexual contacts, blood transfusions, or contaminated needles used for intravenous drug injections; often fatal; high percentage of victims are homosexuals or drug abusers.

Much research is being done on ways to better diagnose and treat AIDS. While it is possible to detect AIDS virus antibodies, scientists are trying to develop a test that would detect the actual virus. Experimental vaccines are also being developed.

The ideal way to stop the spread of STDs would be through vaccines. Despite major attempts to develop STD vaccines, especially for AIDS, only hepatitis A and hepatitis B can currently be prevented with vaccines. These very effective vaccines prevent people from becoming infected with hepatitis A or hepatitis B no matter how they are exposed to it.

Someday, perhaps, the number of STD cases can be greatly decreased. Better tests, more effective drugs, and vaccines can help control STDs. In the meantime, the damage caused by STDs can be reduced by persons being responsible for their own health and the health of any sex partner. The preventive efforts of individual persons is the best way of stopping the spread of STDs.

Assisted by William L. Yarber.


Jackson, Bernard. What Doctors Can’t Heal (Strictly Honest, 1993).

Jackson, James. Wellness (Dushkin Pub, 1992).

McCauslin, Mark. Sexually Transmitted Diseases (Macmillan Child Group, 1992).

Mandel, Bea, and Mandel, Byron. Play Safe: How to Avoid Getting Sexually Transmitted Diseases, 2nd ed. (Center for Health Information, 1986).

Meltzer, A.S. The ABC’s of S.T.D. A Guide to Sexually Transmitted Diseases (Eden, 1983).

Yarber, W.L. STD: A Guide for Today’s Young Adults (American Alliance Publishers, 1985).

Posted 2012/05/05 by Stelios in Education

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HUMAN DISEASES (Part 4 of 7)   Leave a comment

Other Growth Changes

Some alterations in tissue growth are not cancerous. Atrophy, for example, is a lessening in size. It is the shrinking of cells or tissues for various reasons. Starvation, for instance, causes atrophy of the adipose, or fatty, tissues. Disuse of a body part may also lead to atrophy. When a fractured arm is placed in a cast, the arm’s muscles decrease in size from lack of use.

Compensatory hypertrophy, in medicine, condition that results when one of a paired set of organs, such as a kidney or a lung, is removed and the remaining organ increases in size.

Hypertrophy is an increase in size of individual cells or fibres It results in an enlargement of the body part containing these muscles or fibres Hypertrophy of the heart has already been discussed. Compensatory hypertrophy is best seen in paired organs. When a diseased kidney is removed from the body, the remaining kidney grows larger because it now must do the work of two kidneys.


The lungs are spongy organs through which vital oxygen enters the body and needless carbon dioxide exits. Oxygen and carbon dioxide are exchanged in and out of capillaries in the many tiny air sac’s, or alveoli, in the lungs. Although the breathing passages have defences against invading germs and irritants, the lungs can be stricken by a number of serious diseases.

Chronic bronchitis is a disease that results from infection of the air passages by bacteria or viruses. It is marked by cough and increased production of sputum, an accumulation of saliva, mucus, and pus. Air pollution and cigarette smoking both can aggravate the malady.

Tuberculosis, bacterial disease most frequently affecting lungs; associated with fever and loss of weight; commonly transmitted through the air (droplet infection) but also from drinking unpasteurized milk obtained from infected cows.

Tuberculosis is a complicated disease that most often strikes the lungs. The bacilli that cause it grow from place to place in the lung, leaving cavities in the unoccupied sites.

Symptoms of tuberculosis may include weight loss, fever, chest pain, cough, and sputum. After the active infection is arrested, a period follows when the disease may break out again. Tuberculosis is treated with isoniazid and other drugs.

Pneumonia, or acute infection of the lungs, may occur suddenly in a seemingly healthy person. It is usually marked by fever, cough, and chest pain. Lung X rays show patches of inflammation. Though once quite fatal, the threat of pneumonia has been reduced as a result of antibiotic treatment.

Pleurisy, an inflammation of the pleura; caused by infection, injury, or other chest diseases.

Pleura, the serous membrane that covers the lungs, lines the walls of the thorax, and is reflected upon the diaphragm.

Pleurisy is severe chest pain accompanying each deep breath in a person with an inflamed pleura, the twin membrane around each lung and lining the chest cavity. Pleurisy can attend pneumonia or result from direct infection of the pleura.

Emphysema is a serious lung disease that follows destruction of the elastic and connective tissue fibres supporting the lung. It is linked with advancing age. Certain forms of emphysema are inherited. Heavy cigarette smoking and long exposure to air pollutants seem to encourage the disease. A person with emphysema, lacking sufficient lung elasticity, wheezes and has trouble breathing. Furthermore, air movement in the lungs is reduced and the patient is easily fatigued because he fails to get enough oxygen or get rid of enough carbon dioxide.

Asthma is the wheezing or whistling sound that accompanies each breath when the air passages contain too much mucus. It may follow lung infection or result from an allergic reaction that causes muscle spasms and swelling in the air passages.

Acute pulmonary oedema results when fluid quickly accumulates in the lungs and fills the alveoli. The fluid build-up is caused by heart trouble that, in turn, produces back pressure in the pulmonary veins and the left atrium of the heart to which they carry oxygen-rich blood from the lungs. A person suffering acute pulmonary oedema is suddenly breathless and turns blue because of oxygen-poor blood. The condition is treated with oxygen, digitalis to strengthen heart action, and diuretics to speed fluid removal by the kidneys.

Pneumothorax, presence of air in the usually air-free pleural space between the lungs and chest walls.

Pneumothorax occurs when air gets into the chest between the pleural lining. The lung then collapses. A collapsed lung may occur when the chest is pierced in some way or when an abnormal bleb, or blister, on the lung surface bursts.

Lung abscess is an accumulation of a mass of pus inside the lung. A lung abscess can increase the seriousness of pneumonia and other lung infections, especially in chronically ill persons.

Hyaline membrane disease is a disorder of some prematurely born infants. The alveoli of afflicted babies are lined with a protein material, limiting the amount of oxygen their blood can receive. The disease is often fatal.

Histoplasmosis is a fungus infection of the lungs. Fungi lodge in the lungs and multiply until body defences wall them off. In some areas it was once called “summer flu” because its symptoms resemble those of influenza. Serious cases involve weight loss and a long convalescent period.

Silicosis, disease of the lungs, caused by inhaling tiny sharp particles of stone dust; fibrous tissue forming around particles causes cough, shortness of breath, and weakness.

Pneumoconiosis means “dust disease.” It can strike miners and industrial workers who inhale damaging amounts of dust. One of the most serious is silicosis, which results from inhaling quartz dust. Another, anthracosilicosis, arises from inhalation of coal and quartz dust.


Because of its location the skin is perhaps more susceptible to disease than any other body organ. Even so, it is marvellously designed for its particular jobs of protecting the inner body against harm from the outside surroundings, receiving clues about what is happening externally, and keeping the body cool by means of the evaporation of sweat produced by its sweat glands. The skin is thick, leathery, and tough enough to prevent mechanical injury to the body. It is also covered with a barrier of dead cells that block harmful chemicals from getting into the body.

The skin is richly supplied with nerves that enable the perception of pain, touch, heat, and cold. Blood vessels in the skin can either contract or expand in response to nerve signals. A person’s emotional state can often be observed through changes in skin colour Shame or rage reddens the skin; fear blanches it. The skin may react to disease in a great many ways including formation of blisters, pimples, ulcers, tumours, and by haemorrhage

Blackheads are an accumulation of a horny material in special follicles of the face. The characteristic black dots in blackheads are not dirt but melanin, the pigment responsible for skin colour

Acne is an outcropping of blackheads or pimples on the face of an adolescent. It is brought on by hormonal changes that accompany sexual maturity. It is not caused by food, emotions, or uncleanliness. Antibiotics are available for the treatment of severe acne, but most cases respond well to local application of a peeling agent.

Warts are horny growths caused by virus infection. They are spread from person to person. Although warts cannot be prevented, they can be burned away with an electric needle or a caustic chemical such as nitric acid.

Hives, or urticaria, are itchy, whitish elevations of the skin. They appear and disappear rapidly. Hives are often the result of an allergic reaction to certain foods or medicines. Persons who suffer severe cases of hives can receive a series of desensitizing shots. Antihistamine drugs sometimes can relieve a bout of hives.

Birthmark, a skin blemish, result of an overgrowth of blood vessels.

Birthmarks are the result of an overgrowth of blood vessels. They usually show up after birth as port-wine-coloured stains or strawberry-coloured marks. The strawberry marks may eventually disappear but at times can be destroyed quickly by the application of extreme cold. Port-wine stains and other long-lasting skin blemishes can be concealed by special cosmetics.

Eczema, or dermatitis, is a superficial inflammation of the skin. It can be an allergic reaction to poison ivy, dyes, or drugs. It can be provoked by such irritants as acids, solvents, or excessive use of soap or detergents. Sunburn can also cause eczema. Some forms of it, such as infantile eczema and seborrhoeic dermatitis, stem from an unknown cause. Nonetheless, nearly all types of eczema can be relieved by the application of corticosteroid creams.

Athlete’s foot is a fungus infection of the skin between the toes. The infected area is scaly, moist, and itchy. It usually has a disagreeable smell. Athlete’s foot can be relieved when anti fungal drugs are applied to the infected skin each day. Fungus infections that cause a loss of hair or nails must be treated with griseofulvin, an antibiotic.

Bacterial infections such as the psoriasis caused by “staphylococci” germs are rare because of modern standards of hygiene and sanitation. However, the bacterial disease gonorrhoea, which passes between the skin of the sex organs, has risen to epidemic proportions among teenagers in recent years. This and other bacterial infections of the skin are remedied with antibiotics.


The nervous system is the quick communication system of the body. Information from the outside world enters the body through the sense organs and is sent to the spinal cord for instant response or is relayed to the brain for further processing.

Nerves and the membranes that protect portions of the nervous system are susceptible to breakdown or infection. Sometimes, the organisms that cause such diseases as mumps or infectious hepatitis can infect the nervous system, too.

Nervous System Infections

Meningitis is an inflammation of the meninges, or membranes around the brain and spinal cord. It can occur through viruses, bacteria, fungi, or yeasts that get into the nervous system. Meningitis is a serious disease and can be fatal.

Shingles, inflammation of certain nerve tissue caused by virus herpes zoster.

Shingles, or herpes zoster, is a virus-caused inflammation of certain nerve tissue. Painful skin bumps occur over the line of the inflamed nerve or its branches. Shingles and chicken pox are both caused by the same virus.

HUMAN DISEASES (Part 6 of 7)   Leave a comment

Other Metabolic Diseases

Gout is faulty metabolism of purine, an amino acid, resulting in the accumulation of uric acid in the blood and urate salts in the tissues, especially the joints where they cause painful arthritis. It may stem from an inborn error of metabolism or from other diseases. It usually strikes middle-aged men. The joint at the base of the big toe is the typical site of a sudden acute attack of gout. The affected joint becomes red, hot, swollen, and painful. Fever accompanies the attack. Joints of other limbs might become similarly affected. Attacks of gout recur, but the sufferer enjoys complete relief in between them. Some patients develop chronic arthritis from gout. Gout is treated with low-purine foods and such drugs as allopurinol that lower the uric acid level of the blood.

Cystic fibrosis, an inherited disease in which the pancreas fails to provide secretions necessary for normal digestion of food; commonly associated with chronic lung disease.

Cystic fibrosis is a genetic disorder involving the pancreas and the lungs. It appears during the first 10 years of life, although sometimes it is not discovered until later. Certain glands of the pancreas become plugged by thick mucus, which bottles important digestive enzymes. Intestinal troubles result.

Furthermore, the lungs suffer scarring, infection, and eventual emphysema. Cystic fibrosis is treated with substitute pancreatic enzymes, vitamins, and a high-calorie diet. Antibiotics are given to fight the lung troubles.

Other metabolic disorders include phenylketonuria (PKU) and galactosemia. PKU is an inherited inability to metabolize phenylalanine, an amino acid. Galactosemia is an inherited inability to change galactose, one type of sugar, into sucrose, another, because a necessary enzyme is missing. Both diseases can result in mental retardation of children if not corrected in time.

Arthritis and Lupus

Rheumatoid arthritis (RA), chronic disease of the connective tissue, causing painful sensations in joints and muscles.

When the body fails to recognize itself, it makes antibodies against its own tissues. Rheumatoid arthritis and systemic lupus erythematosus are two among a rising number of such autoimmune diseases.

Rheumatoid arthritis is a chronic crippling disease that deforms bone joints and their adjacent tissues. It can strike nearly anyone. Although arthritis is not especially prevalent in damp climates, its symptoms are more bothersome there. It is marked by inflammation of an entire joint, including its synovial lining. Tendon coverings and bursas, or fluid-filled cushions, can become inflamed too. Cartilage in the joint and adjacent bone are destroyed, causing painful stiffness and eventual ankylosis, or “freezing,” of the joint. Skin over the joint is taut, shiny, and clammy. Arthritics often suffer aches and pains. The rheumatoid factor, a large protein molecule, is present in the blood of so many adult patients that it aids in the diagnosis of the disease. Rheumatoid arthritis is usually treated with rest, physical therapy, and aspirin and other salicylates.

Systemic lupus erythematosus (SLE), or lupus, is a serious degenerative disease that can strike one or many body systems over a period of years. The blood serum of afflicted persons contains a number of peculiar proteins, including the so-called L.E. factor, the antibody characteristic of the disease. Symptoms of SLE resemble other diseases, including cancer and tuberculosis, but lesions around the nail beds and fingertips that destroy the skin in those areas earmark lupus. In addition, the spleen and lymph glands of the neck and armpits may enlarge. The pericardium and heart valves are affected too. The kidneys and portions of the central nervous system may also become damaged. Although anyone may be affected, females between the ages of 20 and 40 years most often develop this incurable disease.

Osteoarthritis is a painfully disabling disease of the spine and other weight-bearing joints. Cartilage in the joint is destroyed, followed by overgrowth of nearby bone. The incurable but non deforming disease develops with advancing age.

Ankylosing spondylitis is a disabling and deforming disease of the spine, sacroiliac joints, and sometimes the shoulders, hips, and knees. The synovial lining of the affected joint becomes inflamed, the bone is weakened by loss of calcium, and the spine is bent forward. Eventually, the spinal vertebrae fuse and the spine becomes locked in the deformed position.


Disease can affect any of the parts of the closely related urinary and genital systems. Both can be infected or malfunction because of a shortcoming in development.

Kidney Inflammations

Kidney disease, commonly result of inflammation or damage to blood vessels of kidneys; severe forms lead to breakdown of normal elimination of waste products.

Glomerulonephritis is a serious inflammatory disease of the kidneys. It usually is triggered by a prior infection, often by streptococcal bacteria, which inflames the glomeruli, the tiny tufts through which blood is filtered. The inflammation may go away after a few weeks or may slowly destroy all the glomeruli. In the early stages, the inflammation may reduce filtration enough to cause blood to retain some excess fluid, salts, and wastes. Blood pressure might also rise. If the inflammation persists, the glomeruli are destroyed, blood pressure soars, and urine formation may stop. Mechanical means must be taken to cleanse the blood.

Pyelonephritis, bacterial infection of the inner portions of the kidneys and the urine.

Pyelonephritis is a bacterial infection of the inner portions of the kidneys and the urine. If quickly treated, the infection can be cured. If untreated, however, the infection may scar and eventually destroy kidney tubules, resulting in a need for mechanical cleansing of the blood. Once damaged by a bout of pyelonephritis, the kidneys are easily reinfected.

Toxaemia of pregnancy is a disorder stemming from other kidney problems experienced by some women in the last half of pregnancy. During a pregnancy, the kidneys must work more than usual. However, a woman entering pregnancy with a kidney disease such as Glomerulonephritis may not be able to step up kidney function enough to meet the new demands. In severe cases of toxaemia, the foetus may die or have to be aborted to save the mother’s life. In lesser cases, however, medical treatment poses little risk to either life. Once a woman develops toxaemia, she is likely to develop it again in later pregnancies.

Calculi and Other Urinary Disorders

Calculus disease, condition that occurs when certain substances in urine crystallize into compact stones.

Calculus disease occurs when certain substances in urine crystallize into compact stones called calculi. A stone may be formed within a kidney and become swept by urine into the ureters and the bladder. It may cause pain, obstruct urine flow, or grow large enough to damage the kidney or bladder. Small calculi may be passed in urine, and large ones can be pulverized without surgery by means of energetic sound waves. Calculi can consist of calcium, urates, cystine, or other crystals. The tendency to form kidney stones sometimes runs in families.

Polycystic disease, an inherited failure of normal kidney development, strikes infants as well as adults. Many fluid-filled cysts spring up throughout the kidneys and cause them to malfunction. Polycystic disease sufferers eventually become uraemic

Uraemia means “urine in blood.” It describes the condition in which the kidneys almost totally fail to operate. The blood then retains the nitrogenous products of protein metabolism instead of having them removed by the kidneys. Also, the concentration of many of the electrolytes, or salts, in the blood rises too high. The breath or perspiration of affected persons smells of urine. Each of the previously mentioned kidney ailments could cause uraemia Artificial kidneys have been developed to cleanse the blood of uraemic patients. In some cases, patients with destroyed kidneys can receive a human kidney transplant.

Genital Disorders

Sometimes portions of the genital system fail to develop normally. In some rare cases, the gonads male testes and female ovaries or other sex structures fail to develop at all. Without gonads, a person neither achieves puberty nor develops secondary sexual characteristics, such as breasts and uterus growth in females and penis growth and muscle development in males.

Infections such as gonorrhoea can cause sterility by blocking the oviducts, or egg passages, of females or the vas deferens, or sperm passages, of males. In males, gonorrhoea may also interfere with urination.

The prostate gland at the neck of the bladder in males enlarges slowly with age. It eventually may hamper urination and need surgical correction.


Rehabilitation is a fairly new medical speciality, although the notion of helping someone cope with a disabling disease or disorder is an old one. As an increasing number of people become disabled by stroke, paraplegia (paralysis of the lower body), limb losses, and many chronic nervous system and other physical disorders, it has been shown that medical rehabilitation can help many of them live a reasonably normal life. This is true even when the handicapping problem is not medically correctable.

Rehabilitation means getting utmost use from the limbs, senses, or other body systems that remain in operation after a chronic disability. Its goal is to help the patient become as independently active as possible. The disabling condition might result from a disease, birth defect, or severe accident. Sometimes rehabilitation involves fitting an amputee with an artificial limb, fitting a lame person with a brace, or teaching a paraplegic how to manoeuvre a wheelchair. Sometimes it only involves counselling and other psychological techniques for persons who are mentally disabled.

In its early days medical rehabilitation concentrated on helping people who had walking and other movement problems. The advances made in rehabilitating them sparked efforts to aid people who were stricken by stroke, chronic arthritis, and spinal cord disease and other chronic nervous system disorders. Afterwards, it was learned that rehabilitation could also help patients with heart disease, chronic lung disease, and a variety of conditions that slowed recovery from surgery. Bio engineers have been successful in devising artificial limbs and other life support structures that function so much like natural ones that recipients no longer suffer a disabling handicap.

Rehabilitation is a team effort. It requires the work and dedication of physicians, physical therapists, occupational therapists, psychologists, social workers, and vocational counsellors The doctor and the physical and occupational therapists work to restore those body functions impaired by the disability. The psychologist, social workers, and vocational counsellor help the patient get a mental grip on himself to better deal with the emotional and social problems brought on by the disability. Members of a coordinated rehabilitative team can do wonders in restoring a handicapped person to a functional life.

In addition, the rehabilitative team works with a disabled person to prevent the physical deterioration that takes place when muscles are not used. Furthermore, the team aims at getting the maximum output from the patient’s remaining body functions. Exercises and other means are used to develop fully the remaining physical reserves because disabled persons expend more energy and need more stamina to do ordinary things than do non disabled persons.

Teaching new tasks to the disabled is an integral part of physical rehabilitation. For example, a crippled person may be trained to use a wheelchair or other motive device well enough to manage into the driver’s seat of an auto mobile and thus achieve a measure of independence, the important goal of the entire rehabilitative process.

A chronically disabled person often suffers mental depression. The rehabilitation team tries to restore that person’s confidence so that he can take an optimistic view on resuming daily activities. Positive attitudes of patient, friends, and family toward any disability are important factors in the success of rehabilitation. During rehabilitation the patient is encouraged to find meaning in life, overcome feelings of being a “permanent patient,” and resume his place as an active member of society. Counselling is also important in rehabilitating alcoholics and the mentally ill.

Treatment for the disabled is given at special rehabilitation centres or in the rehabilitation departments of some hospitals. Rehabilitation units are designed so that patients can do many things by themselves; the quarters are built to simulate conditions the patients will encounter when discharged. As a consequence, patients get practice in dealing with such problems as opening and closing doors, going up and down stairs, and a host of other environmental situations that they will face when the rehabilitation program is over.

PARASITES.   Leave a comment

Bed bug

An organism that lives on or within another organism, called the host, and that gains its sustenance from the host organism is known as a parasite. Parasites occur among all the major groups of living things. There are parasitic fishes for example, the lamprey, which attaches itself to other fishes and sucks their body fluids. There are many parasitic arthropods, including fleas, lice, biting flies, and mosquitoes.

Many worms are parasitic. Some live in their host’s digestive tract and feed on the food that passes through. Some attach to the intestinal wall and suck the host’s blood. Some, such as those that cause trichinosis, enter the host through the digestive tract and then burrow into the tissues of the entire body. Some also parasitism plants.

Many fungi are parasitic. The rusts are fungi that are responsible for many diseases of major food plants. Parasitic bacteria are responsible for diseases ranging in severity from acne and tooth decay to such major plagues as the Black Death.

The viruses are unique in that they are all parasitic. They are the smallest of the parasites and may enter the host through the respiratory system or may be spread through sexual contact.


 As originally defined, parasites included any organisms that live by drawing food from a host organism. Defined in this broad way, parasitism included relationships that ranged from benign to harmful and even fatal to the host. The term parasitosis was later developed to describe those forms of parasitism that injure the host, and today the term symbiosis describes benign or even mutually beneficial associations between organisms.

Effects on the host. A parasite’s effect on its host is determined by various factors. Many parasites, for example, do not reproduce in their hosts, or reproduce only to a limited degree. Such parasites, including many parasitic worms, produce eggs that enter another host before they develop. The damage done by such parasites depends in part on the number of parasites in the host, known as the host’s parasite burden. Many hosts can carry a light parasite burden that is, they can support a small number of parasites and suffer no ill effects. A heavy parasite burden, however, may cause severe injury to the host.

In the case of parasites that may undergo unlimited reproduction in their hosts for example, the protozoans, bacteria, and viruses the factors determining the final effect on the host can be quite complicated. The ability of the hosts’ natural defences to destroy the parasites often plays a major role. Very young, old, or weak hosts that have limited defences may be severely harmed by large parasite populations that are able to develop unchecked.

Varieties. Parasites are commonly described in terms of their relationships to their hosts. Parasites that remain on the outer surfaces of their hosts are called ectoparasites. Parasitic arthropods are usually ectoparasites. Endoparasites are parasites that live within the bodies of their hosts. The various parasitic worms that live within the hosts’ digestive tracts are endoparasites. Many endoparasites actually dwell within the tissues of their hosts, not just in the cavities of the hollow organs. The bacterium Mycobacterium tuberculosis, the most common cause of human tuberculosis, lives within the cells of the lung tissues.

Bedbug, a small, flat, bloodsucking insect (Cimex lectularius), of reddish-brown colour, of order Hemiptera, family Cimicidae; is parasitic on humans.

Parasites may be permanent or temporary residents in or on their hosts. The bedbug is a temporary parasite. It crawls onto its host to feed and then returns to its hiding place, where it spends most of its life. The flatworm that causes a form of human schistosomiasis is a permanent parasite. Once it enters a host’s body, it remains there until it dies.

Some organisms can live either as parasites or as free-living forms; they are called facultative parasites. For example, the free-living protozoan Naegleria fowleri, which occurs in streams and lakes around the world, can cause infection of the brain after it enters the noses of swimmers. Other organisms, called obligate parasites, can live only a parasitic existence. Plasmodium falciparum, an organism responsible for a form of human malaria, is an obligate parasite.

Autoecious parasites are parasites that complete their life cycles within a single host. Many parasites, however, have quite complex life cycles and may require more than one host. In some cases the immature stages of the parasite develop in one host, and maturation and sexual development occur in a second host. Hosts in which the immature stages of the parasite develop are referred to as intermediate hosts. Parasites that require two or more hosts to complete their life cycles are referred to as heteroecious.

Malaria, disease consisting usually of successive chill, fever, and “intermission” or period of normality.

The pattern of having more than one host can sometimes provide parasites with a means of spreading. The protozoan that causes malaria has two hosts: humans and certain other animals, and anopheles mosquitoes. Asexual reproduction occurs in infected humans and animals, and sexual maturation, fertilization, and reproduction occur in infected mosquitoes. The protozoans depend on the mosquito to transmit them from one human host to another.

Methods of transmission. An organism that transmits a parasite, as the anopheles mosquito does, is called a vector. Vectors need not transmit parasites by biting, however. Some vectors transmit parasites when they are eaten by the hosts. Certain tapeworms that infect cats and dogs use fleas as vectors. When the cat or dog swallows a flea that is caught during grooming, the immature forms of the tapeworm emerge from the flea’s body and mature in the cat’s or dog’s intestine. The mature tapeworm produces numerous eggs that then pass out of the animal’s body with its faeces and contaminate the environment. If an immature, or larval, flea ingests the tapeworm’s eggs as it feeds on the infected faeces, it becomes infected in turn. The parasite’s life cycle is completed if the cat or dog catches and eats the mature infected flea. A situation such as this, in which a parasite (the tapeworm) is parasitic upon another parasite (the flea), is referred to as hyper-parasitism

Human Parasites

Parasitism in humans is widespread, but the type of parasite varies with geographic regions and social conditions. In areas where sanitation is poor, parasites that are spread by ingestion of faecal-contaminated food and water are common. In areas where housing is inadequate, parasitic insects may be common.

In parts of the world with adequate sanitation and housing, parasites transmitted by faecal contamination and biting insects are generally rare, but those transmitted by direct contact and through the respiratory system may still be common. The parasites that cause measles, mumps, and chicken pox, for example, can spread rapidly in crowded school environments.

Plant Parasites

Arthropod, animal of the phylum Arthropoda comprising invertebrates with external skeleton, segmented body, and jointed appendages.

In many respects the parasites of plants are similar to the parasites of animals. The arthropods, fungi, worms, bacteria, and viruses that parasitic plants may either grow on the plant’s surface or invade the plant’s tissues and, in the case of arthropods that suck plant fluids, may also transmit other parasites, particularly viruses.

Some plants have become parasites on other plants. The simplest form of plant parasitism is that in which the parasitic plant uses its host only for support. The strangler fig, a tropical tree that is grown as a common house-plant, slowly surrounds its host tree until the host dies. The fig then has access to the light above the forest canopy and can grow unhindered.

Other parasitic plants, such as the mistletoe, have a somewhat greater dependence on their plant hosts. Mistletoe grows on trees and uses them for support. In addition, though it makes some of its own food, the mistletoe sends modified roots into its host to draw out nutrients.

Dodder, a leafless parasitic plant introduced into U.S. from Europe with clover seeds; now a rapidly growing pest.

The most complete form of plant parasitism is that in which the parasite relies completely on the host for sustenance. Dodder, for example, is a parasitic vine that draws all its nutrients from its host.

Special Types of Parasitism

Entomologists, scientists who study insects, have described a type of parasitism in which one insect, usually a species of wasp, uses another insect to brood its young. This type of parasitism is called parasitoidism. The parasitoid wasp lays its eggs in or on the host insect, commonly a caterpillar. The wasp’s larvae develop inside the host, feeding on its body, and emerge as full-grown adults. Parasitoidism is being used by some farmers as a means of pest control. Various parasitic wasps, for example, are used to help control agricultural pests.

Another unusual form of parasitism is brood parasitism, which is common among certain birds, particularly the cow-bird and the cuckoo. In this form of parasitism, the parasitic bird lays its eggs in the nest of another species. The host bird then raises the intruder’s young as though they were its own.

A type of parasitism called social parasitism occurs among certain communal insects. Some species of ants, for example, kidnap and enslave the workers of other ant species.

Assisted by Julius P. Kreier, Professor of Microbiology, Ohio State University, and author of ‘Parasitic Protozoa’.

SEXUALITY   Leave a comment

 Human beings are born sexual. Humans develop a strong sense of being male or female. This sense of maleness or femaleness and the behaviour exhibited because of it is called human sexuality. The characteristics of being a man or a woman involve biological, psychological, and sociological behaviours as well as the reproductive capacity and sexual functions of genital organs

Human sexuality is an integral part of life from birth until death. Throughout history people from all cultures have acted in relationships in part on the basis of both physical and emotional feelings of sexual attraction. Sexual behaviour is also influenced by cultural traditions and laws about sex.

Cultures vary greatly in what kinds of sexual behaviour is permitted. In some societies children are discouraged from knowing anything about sexuality and some children are not allowed to understand sexual reproduction. Other societies encourage children to learn about sex. Parents sometimes exercise their right to educate their children about sex and encourage or discourage sexual activity.

Whatever the practice of the society, children grow up aware of the parental, religious, cultural, and social norms of sexual behaviour Human sexuality is also physically influenced by hormones, brain centres, networks of nerves, and sex organs.

Sexual Development

Uterus (or womb), female organ for holding and nourishing young during prenatal development.

Even before birth the female ovaries develop ova, or eggs. At puberty, under the influence of chemicals called hormones that are produced within the body, the ova ripen and are periodically released from the ovaries about once a month. When this event, termed ovulation, occurs, hormones are released to begin a thickening of the lining of the uterus (endometrium). Hormones control the discharge of the lining about once a month. This is called menstruation.

If a woman becomes pregnant, menstruation does not occur; the endometrium stays in the uterus and serves as the first nourishment for the developing embryo. Ovulation and menstruation begin in girls at puberty at about age 12 and continue until menopause, sometime in middle age. Puberty in boys begins when the testes start to produce sperm continuously at about age 13. This is a life-long process in males.

When ovum and sperm come together, the first complete cell of a potential new human begins to develop. This is called conception. Sexual arousal usually precedes conception and begins when hormones are given off by endocrine glands. This causes body fluids to shift to the pelvic area. In the male the fluid goes into the tube called the penis, and in the female through the walls of the tube called the vagina. The fluid also enlarges the labia and the clitoris in females. The testes in the male enlarge and draw close to the body. Eventually the penis becomes erect and the vagina becomes lubricated.

Many body muscles become tense during sexual arousal and stimulation. Continued stimulation of the penis and the clitoris causes a spontaneous release of this tension in a pleasurable feeling called orgasm. In the male, this is most often accompanied by ejaculation. Ejaculate is called semen, a combination of sperm and internal fluids made primarily in the prostate gland. Ejaculation during sexual intercourse places the sperm in the vagina where the spermatozoa move through the opening of the cervix into the uterus and through the fallopian tube. If an ovum is present the sperm will be drawn to it. When a sperm cell penetrates the ovum, other sperm cells are prevented from entering.

Chromosome, microscopic, threadlike part of the cell that carries hereditary information in the form of genes; among simple organisms, such as bacteria and algae, chromosomes consist entirely of DNA and are not enclosed within a membrane; among all other organisms chromosomes are contained in a membrane-bound cell nucleus and consist of both DNA and RNA; arrangement of components in the DNA molecules determines the genetic information; every species has a characteristic number of chromosomes, called the chromosome number; in species that reproduce asexually the chromosome number is the same in all the cells of the organism; among sexually reproducing organisms, each cell except the sex cell contains a pair of each chromosome.

The combination of ovum and sperm make up a complete cell, containing 23 chromosomes from the sperm and 23 from the ovum. These chromosomes carry all the genetic information needed to determine all the inherited characteristics of the potential human being. Of the 23 pairs of chromosomes, one pair, called sex chromosomes, determine male or female sex. Male sperm cells carry either an X or a Y sex chromosome and 22 non sex chromosomes, or autosomes. Ova carry only X chromosomes and 22 autosomes. If an X-carrying sperm cell unites with the ovum, the cell will develop into a female. If a Y-carrying sperm unites with the ovum, the cell will develop into a male. Future male or female body structures are thus determined at conception.

Zygote, in biology, a cell formed by the union of male and female gametes; a fertilized egg cell; earliest stage of development, preceding embryonic and fetal stages.

The new, fertilized cell, now called a zygote, divides until it becomes a ball of cells. It moves into the uterus where it implants itself in the endometrium as a blastocyst. The genital systems of humans appear by the fifth to sixth week of embryonic development. Under the influence of sex hormones, the fetal body differentiates and develops sexual structures by about the seventh week. By the fourth month the foetus’s sex is unmistakably recognizable. This happens under the influence or lack of influence of male hormones testosterone and androgens. The absence of these hormones allows the fetal body to develop as a female. The presence or absence of these hormones is directed by the genes on the XX or XY chromosome pair.

Both male and female reproductive systems develop from the same structural origins. The male fetal structures have female counterparts. (It can also be said that female fetal structures have male counterparts.) Among these structures, called homologous pairs, are the testes and ovary.

Infants experience sexual arousal, which is a biological response, before birth. Young boys experience penile erections, girls vaginal lubrication. In childhood, sex play is a common and normal behaviour When sex play involves the rubbing or self-stimulation of genital organs, it is called masturbation. Masturbation is found in all cultures and is not physically harmful. Many religious groups, however, discourage it.

Sexual arousal expressed in sex play with other children is considered childhood sexuality, not early “adult” behaviour It is a normal exploration of the body and is often pleasurable. In Western culture it is sometimes followed by feelings of guilt because of disapproval from parents or religious authorities.

Adult patterns of sexual development begin at puberty and during adolescence. Hormones cause a rapid growth in height. Sex differences occur in bone and muscle density, breast development, and body and facial-hair patterns. The vagina gradually lengthens and the uterus enlarges. The penis and testes increase in size. Both male and female voices lower. Girls’ bodies begin to grow at about age 12. They usually complete much of their growth rather quickly. Boys begin later, at about age 13, and grow for a longer period of time. Every person is unique in growth rate and development of adult sexual characteristics. It is considered within normal range for the process to begin as late as 16 years.

Feelings of sexual desire begin at puberty. This is often accompanied by fantasy, daydreams, or infatuation. Feelings of sexual attraction can generate social interaction that begins the romance and dating process. At this point, or sooner, boys begin to experience erotic dreams accompanied by orgasm and ejaculation. Girls also experience orgasms during sleep.

Dream, illusion or hallucination of real experiences that occur during sleep.

Normal sleep patterns involve rapid eye movements in about 90-minute intervals. It is during these periods that dreaming, effective rest, slight erections of the penis, and slight engorgement of the labia and clitoris in the female occur. These are biological responses and are not psychologically induced.

Feelings of sexual attraction and attentiveness are a part of the search for self-understanding. Parents and society often guide young people about what is permissible and avoidable sexual behaviour They often caution against the risk of pregnancy, sexually transmitted diseases, and emotional injury. Adults have a desire to protect youths from adverse experiences. Even if sexual feelings are strong, humans can consciously decide whether or not to act on those feelings.

Adolescence is a time for physical, psychological, and social self-discovery. It is a period when children learn about themselves in relation to other people and the community in which they live. Conflict between adolescents and their parents can occur as the search for self-identity leads to a desire for more independence from the family. Parental response during adolescence often includes fear for the health and safety of offspring. Dating is a way in which young people learn about both themselves and the people that attract them. There is a general expectation in many societies that people will choose one marriage partner sometime in young adult years.

Gender Orientation

People grow up knowing themselves as male or female. The human behaviour associated with being a man or being a woman is called gender identity. Among the influences on gender identity are body development, sexual organs, socialization as a boy or a girl, brain hormones that determine our knowledge of our male or female nature, and pubertal hormones that affect both sexual structure and sexual function. Gender identity is related to physical appearances, feelings of arousal and attraction, and desires to dress and act socially in ways considered male or female.

People have both male and female hormones in their bodies. The balance of these hormones allows us to be one sex or the other. Hormonal imbalance in a foetus can cause abnormalities in physical sexual development prior to birth. Cultures promote acceptable behaviours for roles based on sex, called gender roles. Many of these roles are partly determined by the person’s function within the family and economy. In Western culture the family represents a unit based on love, nurture, economic interdependence, and preparation of the young for adult life. For centuries physical work outside the home was perceived as a part of the male role. The female role was to give birth and direct the maintenance of the home. Work-related gender roles have changed. Families often need the earnings of both parents for financial survival. Women work out of necessity, desire, or both. Job qualifications are no longer gender-specific but focus instead on skill, knowledge, and experience.

Sexual Orientation

Homosexuality, the manifestation of sexual desire toward a member of one’s own sex.

What determines whether or not two persons are attracted to one another? The answer to this question is sexual orientation or sexual identity. In the 1940s Alfred Kinsey studied sexual practices in the United States and devised a scale for sexual orientation. The scale ranges from heterosexuality, or basic sexual attraction to the other sex, to homosexuality, or basic sexual attraction to the same sex. Midway on the scale is bisexuality, which means sexual attraction to both sexes. Kinsey concluded that most people do not exhibit exclusively heterosexual or homosexual behaviour Many adults, however, label themselves as one or the other. About 10 percent of the people in Kinsey’s study identified themselves as homosexual. Whether homosexuality was condemned or accepted, every civilization throughout history has included homosexual men and women.

There have been many attempts to explain the origin of sexual orientation. Some believe there is evidence that it is biological. Others believe it is learned behaviour Sexual orientation is very complex and most likely a combination of many factors. There are many religious and cultural attitudes about sexual orientation. Many religions specifically allow, encourage, or condemn various sexual behaviours This may involve an attempt to encourage people to conform to heterosexuality to ensure the continuance of the reproductive family.

Sexual Fantasy

Sexual fantasy or daydreaming is another aspect of human sexuality. This commonly used outlet for sexual feeling can be pleasurable, humorous, and even satisfying. It can also include imagined hostility and behaviours that, if acted upon, would be harmful. Some people feel that portrayals of sex and violence on television and in cinema and music, encourage more sex and violence in real life. There are recorded fantasies of sexual experience with every possible object, animal, or person. During fantasy, the person becomes sexually aroused but usually has no intention of acting out the fantasy. Attempts to act out fantasies are often expressed in art, literature, and the theatre Fantasy portrayed in explicit pictures or words is called pornography.

Attitudes About Sexuality

Western cultural attitudes about sexuality have been greatly influenced by religious attitudes. These came from times of the Old Testament, the Christian church, and the Middle Ages. The Enlightenment, the Puritans in the United States, and Victorian attitudes all have had a profound influence on current sexual attitudes. One attitude, for example, forbids sex outside of marriage. Despite this, society encourages through the media acceptance of various forms of sexual expression in order to entertain. This encouragement often elicits strong reaction from religious communities. Cultural expressions of sexual attitudes are found in religion, novels, films, paintings, music, television, theatre, and formal education. All of these things influence sexual development.

A major role of sex education is to teach the positive nature of sexuality. This aspect is often neglected because priority is given to the perceived danger of pregnancy for young people and of sexually transmitted diseases. The appropriate content of a sex education program is determined by the students’ age level from kindergarten to adult. The purpose of sex education classes is to teach communication and decision-making skills and the anatomy and physiology of the sexual reproductive systems. Classes often include discussions of rape, sexual abuse, abortion, contraception, masturbation, sexually transmitted diseases, pregnancy, childbirth, dating, marriage, and family life. Many religious groups and both public and private schools have sex education programs.

In some communities there are organized groups of adults who oppose sex education in the public schools on the basis of values. It is said that family values about sex are personal and private, that teachers will change that private nature and make statements contrary to family values and beliefs. While the right of parents to teach their children their own values about sex is recognized, there is still debate about the extent to which special interest groups can control sex education in public schools.

Sexuality and Civil Rights

Discrimination, prejudiced or prejudicial outlook, treatment, or action.

Many people concerned with discrimination in society on the basis of sex or sexual orientation become involved with specialized groups that monitor and lobby in government for the rights of all women and men as well as such specific groups as homosexuals, also called gay people. Civil rights groups work toward equal opportunity in employment, housing, and business dealings. There are also concerns about how sexual privacy laws in many states dictate what kinds of sexual practices are allowed for consenting adults or for married people. Many people express a desire to act in any way that is not destructive. The courts deal with issues of the right to mutually consenting behaviour, the sale of pornography, and various forms of discrimination in the workplace.

Sexuality and Health

There are many health concerns related to sexuality. For youths concerns often arise when their bodies begin to mature. Uneven growth, lumps, unfamiliar feelings, and aches can create fear of abnormality. A physician can usually reassure the person of normality or have abnormalities corrected.

Sterility, in biology, the inability to produce offspring; one cause is the production of non functioning sex cells.

Infertility is the inability to get pregnant or to impregnate for a period of time. A permanent state of infertility is called sterility. In men, the most common cause of infertility is low sperm count. In women, failure to ovulate or blocked fallopian tubes commonly cause infertility. Other causes include infections caused by sexually transmitted diseases that scar the tubes, or severe malnutrition, as a result of anorexia nervosa. Infertility is often treated with drugs, microsurgery or artificial insemination.

AIDS (acquired immunodeficiency syndrome), incurable disease caused by a virus that damages the human body’s immune system; believed to be transmitted through sexual contacts, blood transfusions, or contaminated needles used for intravenous drug injections; often fatal; high percentage of victims are homosexuals or drug abusers.

Sexually transmitted disease is a serious public health issue worldwide. Acquired immune deficiency syndrome, or AIDS, is usually transmitted through sexual intercourse, but it can also be transmitted at birth or with blood products. It is fatal. Other sexually transmitted diseases also require medical treatment.

Sexual abuse and molestationare health concerns that involve deliberate sexual acts, often between adults and children. The adults can be parents, older siblings, other relatives, babysitters, neighbours, or strangers. Sexual abuse and molestation occur frequently. When the child or teenager is being stroked, touched, kissed, or sexually approached in any way by an adult, there is an assumed impropriety. Adults who choose children as the object of their sexual desire are called paedophiles Sexual behaviour between close relatives is called incest. Children who grow up with sexual advances from older, more powerful strangers or relatives can get both help and understanding from school or social work professionals.

Sexual therapy. For many reasons, many of them psychological, people can become unable to function sexually. Some experiences in peoples’ lives can cause attitudes about sex that are disturbing. There can also be physical reasons for being unable to function in a sexually satisfying way. This is called sexual dysfunction. For men it commonly results in either the inability to have an erection or unplanned immediate ejaculation after the penis becomes erect. The most common sexual dysfunction in women is the inability to have an orgasm or painful constriction of the muscle at the opening of the vagina when intercourse is attempted (vaginissimus). These problems can occur occasionally or be prolonged and cause anxiety. Sexual dysfunctions are often treated by a therapist in what is called sex therapy.

Assisted by Mary Lee Tatum, teacher and consultant for family life and sex education programs in Virginia.


Bell, Ruth and others. Changing Bodies, Changing Lives (Random, 1980).

Boston Women’s Health Book Collective. Our Bodies, Ourselves, rev. 2nd ed. (Simon & Schuster, 1976).

Calderone, Mary and Johson, Eric. The Family Book About Sexuality (Harper, 1981).

Kelly, Gary. Learning About Sex: The Contemporary Guide for Young Adults (Barron’s Educational Series, 1976).

Madaras, Area and Lynda. The What’s Happening to My Body? Book for Girls (Newmarket, 1983).

Madaras, Lynda and Saavedra, Dane. The What’s Happening to My Body? Book for Boys (Newmarket, 1984).

Nilsson, Lennart and others. A Child Is Born (Delacorte, 1977).


The disease known as AIDS is a complicated illness that may involve several phases. It is caused by a virus that can be passed from person to person. AIDS impairs the human body’s immune system the system responsible for warding off disease and leaves the victim susceptible to various infections.

AIDS was first conclusively identified in the United States in 1981, when 189 cases were reported to the Centers for Disease Control. Within a decade the disease had spread to virtually all populated areas of the world. In the United States alone there are about 65,000 new cases every year. The origin of the AIDS virus is uncertain, but it may have originated in Central Africa.

The first AIDS patients in the Americas and Europe were almost exclusively male homosexuals. Later patients included those who used unsterilised intravenous needles to inject illicit drugs; haemophiliacs (persons with a blood-clotting disorder) and others who had received blood transfusions; females whose male sexual partners had AIDS; and the children of such couples. However, since 1989, heterosexual sex was found to be the fastest growing means of transmission of the virus, with 90 percent of new cases originating from heterosexual sex.

Public awareness of the disease gradually built up as high-profile victims began to die: actor Rock Hudson (1985), clothes designer Perry Ellis (1986), choreographer Michael Bennett (1987), photographer Robert Mapplethorpe (1989), and Oscar-winning director Tony Richardson (1991). When basketball superstar Magic Johnson announced in 1991 that he had contracted the AIDS virus, the feeling spread quickly that anyone, not just particular groups of people, could be at risk. This was again confirmed as tennis legend Arthur Ashe announced in 1992 that he had been infected with the virus for several years.

The AIDS virus. American researchers initially named the virus that causes AIDS the human T-lymphotropic virus, type III or HTLV-III. After researchers discovered in the late 1980s that there were several forms of the AIDS virus, the original virus was renamed the human immunodeficiency virus type 1, or HIV-1.

The virus enters the bloodstream and destroys certain white blood cells, called T lymphocytes, that play a key role in the functioning of the immune system. The virus can also infect other types of cells in the body, including the immune-system cells known as macrophages. Unlike T lymphocytes, however, macrophages are not killed by the virus. In fact, research has suggested that macrophages may carry the AIDS virus to healthy brain cells, to the lymphatic system, and to other healthy cells in the body.

What happens after infection. Most people recently infected by the AIDS virus look and feel healthy. In some people the virus may remain inactive, and these people act as carriers, remaining apparently healthy but still able to infect others. After a few years, some people may develop AIDS-related complex, or ARC. Its symptoms may include fever, fatigue, weight loss, skin rashes, a fungal infection of the mouth known as thrush, lack of resistance to infection, and swollen lymph nodes. Sometimes the symptoms of ARC disappear, but the condition frequently goes on to become AIDS. Though it can take up to 20 years after the virus is contracted for AIDS to fully manifest itself, the average time is one to two years.

The AIDS virus causes so much damage to the immune system that the body becomes susceptible to a variety of opportunistic infections infections that are less harmful to people with normal immune systems but take advantage of the breakdown in an AIDS sufferer’s immune system to produce devastating and eventually lethal diseases. Among the most frequently occurring opportunistic infections are tuberculosis and a type of pneumonia caused by the micro-organism Pneumocystis carinii. AIDS sufferers are also more likely to develop certain tumours, particularly Kaposi’s sarcoma, a rare form of cancer. The AIDS virus may also attack the nervous system and cause brain and eye damage. The average life expectancy for an AIDS victim from the onset of symptoms is one to five years.

How AIDS is spread. AIDS is transmitted by direct contamination of the bloodstream with body fluids that contain the AIDS virus, particularly blood and semen from an HIV-infected person. The virus is usually transmitted through various forms of sexual intercourse, the transfusion of virus-contaminated blood, or the sharing of HIV-contaminated intravenous needles.

The AIDS virus cannot penetrate intact bodily surfaces, such as skin, and quickly perishes outside the human body. Consequently, AIDS is not spread by casual physical contact or by sneezing. The virus has been found in tears and saliva, but it exists there in such low concentrations that transmission from these body fluids is extremely rare. There are no known cases of AIDS transmission by insects such as mosquitoes or by domestic animals. Studies show that the virus is usually passed to an infant close to or during delivery, rather than moving across the placenta during pregnancy. Recently infected mothers can transmit the virus to their children via breast milk. The United States Congress approved guidelines recommending that health care workers who perform invasive procedures be tested for the AIDS virus but the testing and disclosure of results would be voluntary; no restrictions would be placed on those who tested positive.

There are several ways to reduce the spread of AIDS through sexual contact. These include practising abstinence no intercourse or practising safe sex. Practising safe sex means either participating only in a monogamous, or mutually exclusive, relationship in which both people are free of HIV infection, or using latex condoms whenever engaging in intercourse.

Detection and treatment. Usually, when the AIDS virus enters the bloodstream, the body’s immune system produces antibodies to battle the micro-organism Blood tests can detect these antibodies and therefore can indicate exposure to the virus. However, these tests occasionally give false readings and only begin to give accurate results within two weeks to three months after infection, during which time an infected person may pass the virus to others. Scientists do not know exactly how the AIDS virus damages the immune system, nor do they understand why the natural antibodies developed to destroy the virus are ineffective.

By 1987 the drug azidothymidine (AZT) had proved effective in slowing the reproduction of the HIV-1 virus in humans, but it is highly toxic and cannot be taken by many patients. In 1989 researchers determined that lower doses of AZT would be effective and less harmful for patients that have early symptoms of AIDS and for children with AIDS. Dideoxyinosine (DDI) was approved in the United States in 1991 for the treatment of HIV infection. This drug is a useful replacement for AZT and is used in children and other patients for whom AZT is too toxic. In 1992 zalcitabine, or DDC, became the third drug approved to treat people infected with the AIDS virus. It was, however, approved for use only in combination with AZT to treat adults with advanced HIV infection.

Several other drugs and treatments have recently been approved or become available experimentally for the treatment of P. carinii pneumonia, Kaposi’s sarcoma, and other AIDS-related conditions. Several vaccines against AIDS are being developed and tested.


Cozic, C.P., and Swisher, Karin, eds. The AIDS Crisis (Greenhaven, 1991).

Hein, Karen, and others. AIDS: Trading Fears for Facts, updated ed. (Consumer Reports Books, 1991).

Tiffany, Jennifer, and others. Talking with Kids About AIDS (Parent AIDS, 1993).