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.
Stages and Effects of Pyrexia and Hyperpyrexia A pyrexia is a body temperature between 37.60 and 400C and hyperpyrexia is a temperature > 400C. They are conditions in which the thermoregulatory mechanisms are intact but the body temperature is high. Infection s the most common cause of pyrexia and sepsis of hyperpyrexia but there are other causes. A number of drugs have been associated with pyrexia, e.g. diuretics, antiseizure therapy, analgesics, antiarrhythmics and antibiotics. Other causes of pyrexia include neoplasm, surgery, acute myocardial infarctions, heart failure, haemolysis (seen in reactions to blood transfusions) and hyperthyroidism.
Macrocytic Anemia Causes and Treatment Anemias that are associated with macrocytosis (a mean corpuscular volume of >100 fL) include those from liver disease, alcoholism, hypothyroidism, certain drug exposures, megaloblastic anemia, myelodysplasias, preleukemia, or those with marked reticulocytosis due to the larger size of the young erythrocytes.
Kegel Exercises for Women, Benefits and Instruction Are you looking for instruction and benefits Kegel Exercises for Women? A pelvic floor exercise, more commonly called a Kegel exercise (named after Dr. Arnold Kegel), consists of contracting and relaxing the muscles that form part of the pelvic floor, which are now sometimes colloquially referred to as the "Kegel muscles". Several tools exist to help with these exercises, though many are ineffective. Exercises are usually done to reduce urinary incontinence and aid with childbirth in women, and reduce premature ejaculatory occurrences in men, as well as increase the size and intensity of erections.
Causes Of Contact Dermatitis There are many substances that produce contact dermatitis. Occasionally there are people who develop a contact dermatitis during certain seasons of the years. Closer investigation reveals that these people are sensitive to oily fraction of seasonal pollens and plants. Contact dermatitis may also be due to occupational substance such as chemicals, furs, dyes, leather, cosmetics, and many drugs.
when confronted with a condition that is suspected as being contact dermatitis, we try to find out as much information as possible to shed light upon the possible causes.
Smoking Cessation To quit smoking is not easy! For the person who chooses (and it is a choose) to quit, the Mayo Clinic Health Letter offers the following suggestions:
Paleo Diet Plan for Weight Loss The Paleo Diet is a way of eating that is very similar to the way our ancestors allegedly ate during the Paleolithic period, which was about 10,000 years ago. According to the Paleo Diet creator Dr. Loren Cordain the foods suggested in the Paleo Diet are high in the nutrients our bodies need to stay fit, and low in those that contribute to weight gain and illnesses related to too much weight gain.
The creators of the Paleo diet and recipes contend that the human body is genetically made to eat the way our ancestors did prior to the industrialization of agriculture.
Dementia stages symptoms Are you looking for dementia stages symptoms? Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging. It may be static, the result of a unique global brain injury, or progressive, resulting in long-term decline due to damage or disease in the body. Although dementia is far more common in the geriatric population, it can occur before the age of 65, in which case it is termed "early onset dementia".
Symptoms of dementia can be classified as either reversible or irreversible, depending upon the etiology of the disease. Less than 10% of cases of dementia are due to causes that may presently be reversed with treatment. Causes include many different specific disease processes, in the same way that symptoms of organ dysfunction such as shortness of breath, jaundice, or pain are attributable to many etiologies.
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.
Tamiflu Side Effects Children Tamiflu side effects in children
New research claims that “more than half of children taking Tamiflu to combat swine flu suffer side effects such as nausea, insomnia and nightmares,” said The Daily Telegraph. It also said the study suggests that one in five children who took part reported having a neuropsychiatric side effect, such as poor concentration, inability to think clearly, problems sleeping, and feeling dazed or confused.
Pseudogout crystals Pseudogout crystals are small enough and dull enough that they’re relatively difficult to see. Well, how do you see them? You take a pallet spin it down or take fluids spin it down to a pallet resuspend it, your chances of seeing pyrophosphate crystals go up about 70% or if you use a pallet. This is clinically an acute podagra. The inflammation is so intense that you actually peel off the skin like a blister. How come this is not cellulitis, sometimes it is difficult to sort out, as I say, the two can co-exist. The location is consistent with gout; in this particular case you can see tophaceous draining. This is chronic polyarticular tophaceous gout in a female patient that mimics rheumatoid arthritis. No history of acute podagra, this patient is 75 years of age, underlying osteoarthritis with crystal deposition disease. Different disease in men and women.
Transient ischemic attacks Symptoms and Treatment Transient ischemic attacks (TIAs) are neurogical deficits (such as loss of vision in one eye, inability to speak, paralysis, or weakness of one side of the body) of sudden onset that last for less than 24 hours. Although they are symptomatically similar to minor strokes, they do no discernible lasting damage to brain function.
The major importance of TIAs is their role as a predictor of stroke. When a person describes a “light stroke”, it is often a TIA that is meant. If left untreated, TIAs can indeed lead to major strokes, with permanent damage to all parts affected.
Enlarged Heart Treatment Enlarged heart Definition
Enlarged heart (cardiomegaly) isn't a disease, but rather a symptom of another condition.
Cocaine Effects on The Brain and Body At one time cocaine was considered the drug of upper-class America. Unfortunately, the use of cocaine and its derivative, crack, is now epidemic. It is estimated that 25 to 30 million people have experimented with cocaine in the United States. Approximately 5 million people use the drug regularly. Among young adults, 6,7% have tried crack and 40% tried cocaine. In a recent survey of high school senior, 1 in 18 admitted to trying crack and 14% used cocaine in other forms.
A powerful stimulant, cocaine is derived from the leaves of the South American coca shrub and ground into a crystalline powder. The most common methods of sung the drug are either snorting it, liquefying it and then injecting it, or freebasing (smoking). When snorted, the white powder is sniffed up through the nose. The most potent and expensive method of cocaine use is freebasing. The drug is usually smoked in a water pipe because this provides faster absorption into the bloodstream.