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.
Psoriasis Symptoms in Children Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get them on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your body. A problem with your immune system causes psoriasis. In a process called cell turnover, skin cells that grow deep in your skin rise to the surface. Normally, this takes a month. In psoriasis, it happens in just days because your cells rise too fast. Here is some stuff about Psoriasis Symptoms in Children.
How to Managing Your Weight Managing your weight is not an easy task. To ensure success, you must a real change in the way you eat and consider it a lifelong commitment rather than a diet. Analyzing where you are right now and then taking steps outlined below will help you lose excess weight
Gout diet recipes Gout, a painful form of arthritis, has long been associated with diet, particularly overindulgence in meat, seafood and alcohol. As a result, gout treatment used to include severe dietary restrictions, which made the gout diet hard to stick to. Fortunately, newer medications to treat gout have reduced the need for a strict gout diet.
A gout diet reduces your intake of foods that are high in purines, which helps control your body's production of uric acid. If you're overweight or obese, lose weight. However, avoid fasting and rapid weight loss because these can promote a gout attack. Drink plenty of fluids to help flush uric acid from your body. Also avoid high-protein diets, which can cause you to produce too much uric acid (hyperuricemia).
Radiation Safety Principles and Standard
The International Commission on Radiological Protection (ICRP) has
proposed that following principles should guide the use of ionizing
radiation safety standard:
No practice involving exposures to radiation should be adopted unless it
produces sufficient benefit to the exposed individuals or society to offset
the radiation detriment it causes (the justification of practice)
In relation to any particular source within a practice, the magnitude of
individuals doses, the number of people exposed, and the likelihood on
incurring exposures where these are not certain to be received should all kept
as low as reasonably achievable (ALARA), economic and social factors being
taken into account. This procedure should be constrained by restrictions of
the doses to individuals (dose constraint), so as to limit the inequity likely
to result from the inherent economic and social judgments.
The exposure of individuals resulting from the combination of all the
relevant practices should be subject to dose limits, or to some control of
risk in the case of potential exposures. These are aimed at ensuring that no
individual is exposed radiation risks that are judged to be unacceptable from
these practices in any normal circumstances. Not all sources are susceptible
of control by action at the source and it is necessary to specify the sources
to be included as relevant before selecting a dose limit.
Cerebral Palsy Definition Sign and Treatment Cerebral Palsy Definition
Cerebral palsy (CP) is an umbrella term encompassing a group of non-progressive, non-contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement.
Cerebral palsy types, symptoms and treatment Cerebral palsy (CP) is a general term to describe various disorders of muscle control caused by a period of lack of oxygen to the brain.
Cerebral palsy Causes
Cerebral palsy is caused by brain or nerve damage that usually occurs before or around the time of birth. The damage may result when brain tissue becomes starved for oxygen for any reason. It may result from separation and bleeding of the placenta (the organ that anchors the fetus to the wall of the uterus and provides nourishment) in late pregnancy or form disorders caused by diabetes in the mother. It is characteristic of cerebral palsy that the neurologic problems are not progressive.
Physical Allergy Some persons, when exposed to changes in temperature such as cold or heat or when exposed to sudden effort or sunlight, may develop manifestation, such as asthma, hay fever, or hives. In these instances the cold or heat acts as an antigen, much the same as milk or pollen may produce allergy. The demonstration of the presence of such sensitivity requires special tests. In the case of a patient sensitive to cold one tests the patient by attaching a small tube containing ice water to the skin of the arm. The tube is held in place with adhesive. Sensitivity to cold is determined by the appearance of large welt or hive at the point of contact. A similar of allergy are also included those patients who when exposed to a draft or a cod breeze develop nasal symptoms followed by severe so-called sinus headaches.
Enlarged Heart Treatment Enlarged heart Definition
Enlarged heart (cardiomegaly) isn't a disease, but rather a symptom of another condition.
What is a Low Glycemic Diet A recent Harvard study found that a low-glycemic diet was the best of three popular diets at both maintaining metabolism during weight loss and maintaining cardiovascular health. But what is it and what are low glycemic foods anyway?
The diet, which is also known as the glycemic index diet or GI diet, emphasizes unprocessed foods, complex carbs and food combining. It was originally developed as a diet to help diabetes patients regulate their blood sugar and, according to WebMD, is still most effective in this capacity. Many popular diets, including Nutrisystem, the Zone diet, Sugar Busters and South Beach diet incorporate low-glycemic principles.
Pleurisy symptoms back pain Pleurisy (also known as pleuritis) is an inflammation of the pleura, the lining of the pleural cavity surrounding the lungs. Among other things, infections are the most common cause of pleurisy.
The inflamed pleural layers rub against each other every time the lungs expand to breathe in air. This can cause severe sharp pain with inhalation (also called pleuritic chest pain). Here is some stuff about pleurisy symptoms back pain.
Neutralization Therapy Neutralization therapy is an extension of the provocation-neutralization testing procedure in which specified doses of allergen extracts are used by the patient to relieve symptoms. It is also called "symptom-relieving" therapy and "tolerance." Advocates recommend it for both treatment and prophylaxis.
Chrons disease symptoms in children Are you looking for chrons disease symptoms in children? Crohn's disease, also known as regional enteritis, is an inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms. It primarily causes abdominal pain, diarrhea (which may be bloody if inflammation is at its worst), vomiting, or weight loss, but may also cause complications outside the gastrointestinal tract such as skin rashes, arthritis, inflammation of the eye, tiredness, and lack of concentration.
Heat Stroke Long Term Effects Are you looking for heat stroke long term effects? here is some good article about heat stroke long term effects.
Heat stroke is a form of hyperthermia, an abnormally elevated body temperature with accompanying physical symptoms including changes in the nervous system function. Unlike heat cramps and heat exhaustion, two other forms of hyperthermia that are less severe, heat stroke is a true medical emergency that is often fatal if not properly and promptly treated.