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.
Scarlet fever rash picture, symptoms and treatment Scarlet fever (sometimes referred to as scarlatina) is an infectious disease characterized by fever, sore throat (pharyngitis), and a characteristic rash. Scarlet fever is caused by an infection with group A Streptococcus, the same bacteria responsible for causing "strep throat" and various other skin infections (for example, impetigo and erysipelas). Scarlet fever is predominantly a childhood disease occurring in children 2-10 years of age, though it can less commonly occur in older children and adults. The incidence and mortality rates associated with this once feared disease have significantly decreased due to the introduction and widespread use of antibiotics.
Watermelon diet plan Are you looking for watermelon diet plan? The Watermelon Diet comes in and out of vogue regularly. That itself should be a warning - watermelons are highly seasonal, so there are only a couple of months of the year that fresh watermelons are even available. When they are, the hype surrounding this silly fad diet returns too.
Whilst there is no single "official" watermelon diet plan, the generally touted concept is that, to lose weight, you should eat nothing but watermelons for a few days, or a week, or a couple of weeks. The theory is that they are nutritious, filling and low in calories.
Endometriosis Symptoms Checklist and Sign Endometriosis is the abnormal growth of cells (endometrial cells) similar to those that form the inside of the uterus, but in a location outside of the uterus. Endometrial cells are cells that are shed each month during menstruation. The cells of endometriosis attach themselves to tissue outside the uterus and are called endometriosis implants. These implants are most commonly found on the ovaries, the Fallopian tubes, outer surfaces of the uterus or intestines, and on the surface lining of the pelvic cavity. They can also be found in the vagina, cervix, and bladder, although less commonly than other locations in the pelvis. Rarely, endometriosis implants can occur outside the pelvis, on the liver, in old surgery scars, and even in or around the lung or brain. Endometrial implants, while they can cause problems, are benign (not cancerous).
Rheumatoid Arthritis Diet Cure and Foods to Avoid Rheumatoid arthritis is primarily an inflammatory disease. It is an
autoimmune disorder whereby the body's own immune system starts attacking joint
tissue. A chronic disease, it tends to progress over time, but many people find
the pain and stiffness come and go for far varying periods of time. Rheumatoid
arthritis affects three times as many women as men. It is now thought that over
acidity in the body and uric acid deposits in the joints are major contributing
Researches in England have found that at least one third of people can
completely control their Rheumatoid arthritis bu eliminating foods to which they
have a sensitivity. The most common culprits are any foods and drinks containing
cow's milk as well as the nightshade group of fruit and vegetables.
Hypertension Symptoms Diagnosis and Treatment High blood pressure is defined as a systolic BP ≥ 140 or a diastolic BP > 90
on more than two occasions (see Table 3.5). Hypertension is associated with
MI, heart failure, stroke, and kidney disease and has a higher prevalence
among ethnic minorities, in women, and with ↑ age. As a screening measure,
BP should be checked at least every two years starting at age 18.
Guidelines for Exercise in the Cold Problems related to exercise in cold weather include frostbite and hypothermia (abnormally low body temperature). Frostbite can lead to permanent damage loss of a body part from gangrene. This can be prevented by adequately protecting exposed areas, such as fingers, the nose, ears, facial skin, and wrists. A stocking hat is preferable for two reasons: (1) blood vessels in the scalp do not constrict effectively, so a significant amount of heat is lost if a head covering is not worn, and (2) a stocking-type hat can be pulled down to protect the ears. In very cold or windy weather, you can use surgical or ski masks and scarves to keep facial skin warm and to moisten and warm inhaled air. All exposed or poorly protected flesh is vulnerable to frostbite when the temperature is low and the wind chill high.
Treatments for Endometriosis Adenomyosis is endometriosis in the endometrium, specifically in the musculature, and if it is found below the basement membrane. Endometriosis has been found in an estimated ten percent of the general population. This was found a long time ago when we did tubal ligations on patients and saw endometriosis in normal fertile patients. However, endometriosis has been found in about twenty-five to thirty percent of infertile patients undergoing laparoscopy. So what are Treatments for Endometriosis?
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Sinusitis Symptoms and Treatment Sinusitis is an infection (usually bacterial) of one or more of the sinuses. It occurs more commonly in adults than in children. The sinuses are air-filled cavities located within the facial bone structure and connected to the nose. There are four major groups; frontal, ethmoidal, sphenoidal, and maxillary.
The sinuses are lined with mucous membrane and are normally kept clear when mucus drains through them into the nasal passages. If they are obstructed, normal drainage cannot occur, and infection of the sinuses can result.
Body Odor Causes The primary function of the eccrine sweat glands is to assist in the maintenance of body temperature in response to heat exposure or exercise. Hyperhidrosis may be defined as sweating beyond what is necessary to maintain thermal regulation. It may be primary (idiopathic, essential) or secondary to a number of diseases and prescribed drugs. Hyperhidrosis can be localized or generalized. Regardless of the type or cause of the hyperhidrosis, it is frequently socially embarrassing and occupationally disabling.
Hiatus Hernia Treatment The term hiatus hernia describes diaphragmatic hernia or weakness in the diaphragm, the horizontal muscular wall separating the organs of the chest from the organs of the abdomen. A hernia is an abnormal protrusion of an organ or tissue through an opening. A hiatus, or opening, permits the esophagus to carry food from the mouth to the stomach. Blood vessels and nerves also pass through the diaphragm. The diaphragm is an important group of muscles for contracting and expanding the lungs, forcing air in and out of the lung tissues.