Immune System Facts Information and Function for Kids
2011-03-23 > Various
What is Immune System
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own healthy cells and tissues in order to function properly.
Detection is complicated as pathogens can evolve rapidly, and adapt to avoid the immune system and allow the pathogens to successfully infect their hosts.
Immune System Function
The immune system is composed of many interdependent cell types that collectively protect the body from bacterial, parasitic, fungal, viral infections and from the growth of tumor cells. Many of these cell types have specialized functions. The cells of the immune system can engulf bacteria, kill parasites or tumor cells, or kill viral-infected cells. Often, these cells depend on the T helper subset for activation signals in the form of secretions formally known as cytokines, lymphokines, or more specifically interleukins.
The Organs of the Immune System
All the cells of the immune system are initially derived from the bone marrow.
In the thymus gland lymphoid cells undergo a process of maturation and education prior to release into the circulation. This process allows T cells to develop the important attribute known as self tolerance.
The spleen is an immunologic filter of the blood. It is made up of B cells, T cells, macrophages, dendritic cells, natural killer cells and red blood cells.
Lymph nodes are small bean shaped structures lying along the course of lymphatics. They are aggregated in particular sites such as the neck, axillae, groins and para-aortic region.
Killer T cell are a sub-group of T cells that kill cells that are infected with viruses (and other pathogens), or are otherwise damaged or dysfunctional. As with B cells, each type of T cell recognises a different antigen. Killer T cells are activated when their T cell receptor (TCR) binds to this specific antigen in a complex with the MHC Class I receptor of another cell. Recognition of this MHC:antigen complex is aided by a co-receptor on the T cell, called CD8. The T cell then travels throughout the body in search of cells where the MHC I receptors bear this antigen. When an activated T cell contacts such cells, it releases cytotoxins, such as perforin, which form pores in the target cell's plasma membrane, allowing ions, water and toxins to enter. The entry of another toxin called granulysin (a protease) induces the target cell to undergo apoptosis. T cell killing of host cells is particularly important in preventing the replication of viruses. T cell activation is tightly controlled and generally requires a very strong MHC/antigen activation signal, or additional activation signals provided by "helper" T cells.
Abdominal Pain Symptoms and Treatment A common primary care problem, especially among females, that is most oftenbenign but can be related to serious diagnoses. Functional pain is the
most common recurrent form of pain. Generally a diagnosis of exclusion, it is
defined as nonorganic pain related to everyday stress. School, peer, and family
problems are commonly associated stressors. Abdominal pain can be related
to school absenteeism and may be a sign of depression.
Adrenal Insufficiency Causes, Symptoms and Treatment Autoimmune adrenalitis is the most common cause of primary adrenal insufficiency. Adrenalitis caused by tuberculosis was once the most common cause. Autoimmune adrenalitis is sometimes accompanied by other autoimmune endocrine deficiencies, such as thyroid disease, diabetes mellitus, pernicious anemia, hypoparathyroidism, or ovarian failure (Table 14). Recently, AIDS and antiphospholipid syndrome have been cited as additional causes.
Iatrogenic tertiary adrenal insufficiency, a common secondary cause of adrenal insufficiency, results from suppression of hypothalamic-pituitary-adrenal function secondary to glucocorticoid administration. Secondary adrenal insufficiency may also result from pituitary or hypothalamic disease, as described earlier.
Symptoms bowel cancer Are you looking for symptoms bowel cancer? Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth (neoplasia), in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus.
Colorectal cancers start in the lining of the bowel. If left untreated, it can grow into the muscle layers underneath, and then through the bowel wall. Most begin as a small growth on the bowel wall: a colorectal polyp or adenoma. These mushroom-shaped growths are usually benign, but some develop into cancer over time. Localized bowel cancer is usually diagnosed through colonoscopy.
Drugs for Depression Are you looking for drugs for depression? here is some good stuff about drug for depression.
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behavior, feelings and physical well-being. It may include feelings of sadness, anxiety, emptiness, hopelessness, worthlessness, guilt, irritability, or restlessness.
Scurvy Causes, Symptoms, Diagnosis, Treatment and Prevention Scurvy is a disease caused by vitamin C deficiency. It is characterized by anemia (deficiency of red blood cells), spongy gums, a tendency to bleed and abnormal bone and tooth formation. The disease may be either acute (short-term) or chronic (long-term).
Vitamin C is essential for the formation and maintenance of connective tissue, bone tissue, and teeth. It is also essential for the healing of wounds and burns.
What is Marijuana and the Effects on Brain and Body Approximately 25 years ago, marijuana became a cultural phenomenon, the symbol of one generation's disregard for another. The marijuana found on the streets at that time, however, lacked the potency of current crops. Crossbreeding of more potent variates, improved cultivation, and the part of the plant being used all contribute to increased levels of the delta90-tetrahydrocannabinol (THC), the major psychoactive drug found in marijuana. Some marijuana currently grown in the United States rivals the previously stringer varieties of Mexico, Jamaica, and other areas. The THC percentage of Cannabis saliva (the Indian hemp plant which marijuana is derived) in plants grown in the United Sates can range from 2% to as high as 7%. The higher the percentage of THC , the more potent the drug. Marijuana is composed of the dried leaves and flowering tops of the cannabis plant. Hashish, which has stronger effects, is processed from called hash oil. Marijuana is seed motor extensively than hashish in the United States.
Allergy In Children The importance of an early diagnosis of allergy cannot be overemphasized. This diagnosis should be made in infancy or early childhood. This involves not only recognition that the condition affecting the child is allergic, but also a serious attempt at discovering the cause of the allergy. In doing this, however, one meets frequently with great deal of resistance by the mother because she does not want to see the child hurt, r because she somehow has a vague suspicion that skin testing endangers the child's health. The mother must understand the importance of such an early diagnosis. She must realize that delay is equivalent to neglect, and that neglect needlessly expose the child to the dangers of complications which may result from an untreated allergy a case of hay fever or case of asthma in a child. After a few years, however, this condition becomes complicated by nasal infection or by bronchitis, or by changes in the tissues of the lungs. These changes become refractory to treatment, so that even if the allergy is discovered, treatment of complications becomes difficult if not impossible. The mother must also understand that skin testing, if properly done, is not dangerous and does not affect the child's physical condition.
Treatment Of Sleep Disorder Primary Insomnia
Relaxation therapies can be helpful in the treatment of chronic insomnia, hypnosis, meditation, deep breathing, and progressive muscle relaxation are effective. Success with these interventions requires a great deal of practice and motivation on the part of the client.
Biofeedback has been used with success in some clients. The use of biological variable, such a asectromyography, helps these clients increase sensitivity to their internal state of arousal.
Bones and Muscles The bones of the human body, securely attached together by ligaments, form the skeleton or framework of the body. The body tissue, organs, and systems are located either inside the cavities formed by the skeleton or around it. The skeleton is the framework that holds everything in place. Also it source of attachment for many of the organs.
Symptoms Ovarian Cancer Are you looking for article about symptoms ovarian cancer? Here is good stuff about ovarian cancer symptoms.
The 5-year survival rate for ovarian cancer by stage is not significantly different from the 5-year survival rate for other gynecologic cancers; however, there is a significant difference in stages, with ovarian cancer usually having spread into the abdomen in about two thirds of patients at the time of diagnosis. It is clear from these data that the single most important factor in the large number of deaths from ovarian cancer is the failure to diagnosis the disease at an early stage. The reasons for this failure correspond to the growth and spread patterns of the disease. Because the ovary floats freely in the pelvic cavity, a tumor can grow for some time without producing symptoms associated with involvement of, or pressure on, other organs.
Over the counter ringworm treatment for kids Are you looking for over the counter ringworm treatment for kids? What will you do if you see red itchy patches on your body? It may be a case of ring worm infection. It may sound bad, but it can be cured easily with over-the-counter ringworm treatment.
Ringworm is a common skin infection caused by a fungus. The fungi feeds on the dead cells of skin and hair causing a ring of irritated itchy skin that looks like a worm. This may cause a rash and becomes sore. It may appear as scalp ring worm, body ringworm, face ring worm or groin ringworm.
Drug Classification Drugs are commonly classified according to the physiological effect they have. Categories include stimulants, depressants, hallucinogens, narcotics, and inhalants. Two other types are also important. First, designer drugs are manufactured to mimic the effects if drugs found in the previously mentioned categories. Designer drugs usually are not illegal because their chemical formula has been altered from the original drug. The other drug, marijuana, is difficult to classify but is usually included as a hallucinogen. Depending on the dose, marijuana can mimic a variety of substances found in other categories.
What is Allergy A person is said to be allergic if he reacts to a substance in a manner different from the ordinary or normal person. Thus to most of us an egg is harmless and wholesome food-yet in certain persons even a small amount of egg may produce such symptoms as swelling of the lips, a skin rash, or even severe asthma. Such persons may be normal in every other respect except for this peculiarity or idiosyncrasy, and so we say of such persons that they are hypersensitive to egg protein or, in medical parlance, that they are allergic.