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.
What is Vitamin D for Health Are you looking for what is vitamin d for health?
Vitamin D is very important for the health and it is true fact that vitamin is not found in our foods as compare to its need in the body. Other major and most important source of vitamin d is sun light. But in this era world is fast enough that none of us has enough time to get sub bath and get vitamin via their skin.
Natural cure for leukemia Are you looking for Natural cure for leukemia? Leukemias are grouped by how quickly the disease develops (acute or chronic) as well as by the type of blood cell that is affected (lymphocytes or myelocytes). The four main types of leukemia include acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myelocytic leukemia (AML), and chronic myelocytic leukemia (CML). But most people who have these risk factors don't get leukemia. And most people who get leukemia do not have any known risk factors.
Facing Cancer While heart diseases mortality rates have declined steadily over the past 50 years, cancer mortality rates have increased consistently in the same period. Based on current rates, about 83 million-or one in three of us now living-will eventually develop cancer. Many factors have contributed to the rise in cancer mortality, but the increase in the incidence of the lung cancer is probably the most important reason. Despite these gloomy predictions, recent advancements in the diagnosis and treatment of many forms of cancer have reduced much of the fear and mystery that once surrounded this disease.
Concussion Symptoms and Treatment Concussion is an injury to the brain, caused by a violent jar or shock, such as a blow to the head. The force of the shock causes the brain to strike against the inside of the skull, producing temporary brain swelling and malfunctioning and often loss of consciousness. The shock may even be strong enough to cause cerebral contusion (bruising of brain tissue), cerebral hemorrhage (bleeding between covering of the brain and the skull or inside the brain covering), or formation of a hematoma (collection of clotted blood).
Types of Blood Cancer Symptoms and Treatments Overview of Blood Cancer
The major forms of blood cancer are lymphoma, leukemia and multiple myeloma. These cancers are formed either in the bone marrow or the lymphatic tissues of the body. They affect the way your body makes blood and provides immunity from other diseases.
Bladder cancer Symptoms and Treatment Here is som stuff about Bladder cancer sign and Symptoms and bladder cancer treatment. The etiology of bladder cancer is not well understood. Like most other malignancies, it is an environmental cancer. About 50% of bladder cancers can be accounted for on the basis of cigarette smoking. There is a dose-response relationship between the amount of cigarettes smoked and the likelihood of developing bladder cancer.
Teenage Acne Treatment Girls Are you looking for teenage acne treatment for girls? Acne is caused when a hair follicle get clogged with an oil called sebum and skin cells. Skin bacteria thrive and multiply in sebum, causing inflammation. Some acne consists of simple blackheads and whiteheads. Inflammation within the pore causes a pimple (also called a “papule”) or a pus-filled pimple (“pustule”), depending on how deep it is. If it’s really deep, it can cause a painful cyst and scarring.
The Foetal Circulation To understand the foetal circulation, it must be appreciated that the foetus develops its own blood and that at no time does the foetal and maternal blood mix unless some pathological process is present. The foetus produces its own red and white blood corpuscles. During intrauterine life the foetal gastrointestinal and respiratory system are not functioning, so the maternal blood furnishes the necessary nutrients and oxygen through the placenta, which in this case acts as the organ of respiration.
FOODS CAUSE OF ALLERGY People may be sensitive to single or to multiple foods. Here again are some foods which are botanically related, so that if a patient is sensitive to one food in this group, he sensitive to the others. Examples of this may be cited in the case of cabbage, Brussels sprouts, and cauliflower. Many of the sea foods and fresh water fish are thus similarly related; so that if a patient is sensitive to one type of fresh water fish, he is likely sensitive to the others. The most frequent allergy-producing foods are common foods, namely, milk, eggs and wheat, fish and nuts. It is unfortunate that this is the case because these are also essential foods, and this avoidance becomes a serious problem in undernourished people and in children of infants. When a patient is definitely sensitive to one or two foods only, it is not difficult for him to realize it himself. The difficulty arises, however, when he is allege to many foods. Under these circumstances he is likely to become confused and then he needs a physician's help. Allergy to a food may be of various degrees of severity. Symptoms of asthma or hives may not arise if only one food is eaten if the sensitivity is mild. However, if a number of such foods are ingested at one time, the symptoms may be pronounced. Another factor which is important in connection with the production of symptoms is the readiness with which a food is absorbed from the gastrointestinal tract. The quicker the absorption, the more rapid will the symptoms develop after eating.
Hemroid Cure Treatment Are you looking for hemroid cure treatment? Hemorrhoids are swollen veins in the anal canal. This common problem can be painful, but it’s usually not serious.What causes hemorrhoids?
Too much pressure on the veins in the pelvic and rectal area causes hemorrhoids.
Normally, tissue inside the anus fills with blood to help control bowel movements. If you strain to move stool, the increased pressure causes the veins in this tissue to swell and stretch. This can cause hemorrhoids.
Diarrhea or constipation also may lead to straining and can increase pressure on veins in the anal canal.
ADHD Symptoms in Children Are you looking for ADHD Symptoms in Children? Attention deficit hyperactivity disorder (ADHD or AD/HD or ADD) is a developmental disorder. It is primarily characterized by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age. ADHD is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3 to 5 percent of children globally and diagnosed in about 2 to 16 percent of school aged children.
Failure patterns of combined modality treatment in lung cancer By C.J. Hoekstra, H. Rijna, E.F. Smit, J.C. van Mourik, P.E. Postmus, A.A. Lammertsma, O.S. Hoekstra 17
Background: Patients with locally advanced non-small cell
lung cancer (NSCLC) may be treated with induction
chemotherapy (IC) followed by surgery with curative
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