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.
Best countries for Plastic Surgery Are you looking for Best countries for plastic surgery?
Cosmetic plastic surgery includes surgical and nonsurgical procedures that reshape normal structures of the body in order to improve appearance and self-esteem. Healthy individuals with a positive outlook and realistic expectations are appropriate candidates for cosmetic procedures. Plastic surgery is a personal choice and should be done for yourself, not to fulfill someone else's desires or to try to fit an ideal image. Because it is elective, cosmetic surgery is usually not covered by health insurance.
Alternative Therapies for Asthma You probably have heard of several so-called "alternative" therapies for asthma. These are treatments that are not conventional and are usually given by nonmedical people. Most of these "treatments" do not help asthma and are often very expensive. However, people are sometimes tempted to try alternative therapy, which is often advertised by means of testimonials as having great benefit. People always hope that this will provide
a "cure" and allow them to stop their asthma treatments.
It should be stressed that these treatments have no proven benefit when tested in
proper clinical trials, although there may appear to be some improvement at first because
of the "placebo" effect, since suggestion may, for a short time, improve asthma symptoms.
Bunion surgery recovery and photos Are you looking for Bunion surgery recovery and photos? Bunion surgery generally involves an incision in the top or side of the big toe joint and the removal or realignment of soft tissue and bone. This is done to relieve pain and restore normal alignment to the joint. If the joint is severely deformed, it may be stabilized with tiny wires, stitches, screws, or plates. There are no guarantees that a bunion surgery will fully relieve your pain.
The kind diet recipes and review Like many celebrities before her, actress Alicia Silverstone has put together a book that she says reveals the secrets of her great looks and knockout figure. In The Kind Diet, Silverstone attributes her health and beauty to her totally organic, vegan diet, free of "nasty" meat, dairy, white sugar, and processed foods.
In The Kind Diet, Silverstone, a passionate animal activist and conservationist, says a plant-based diet is not only good for your body but also saves animals and is one of the "greenest" things you can do. here is some review for The kind diet.
Dash Diet Recipes Meal Plans The DASH diet (Dietary Approaches to Stop Hypertension) is a diet promoted by the National Heart, Lung, and Blood Institute (part of the NIH, a United States government organization) to control hypertension. The first study was utilized by its inital founder, Nick Dash, in 2004 while he was serving in the Armed Forces. Nick provided the Government with the study which was later incorporated in 2008. The Dash diet is rich in fruits, vegetables, whole grains, and low-fat dairy foods; includes meat, fish, poultry, nuts and beans; and is limited in sugar-sweetened foods and beverages, red meat, and added fats. In addition to its effect on blood pressure, it is considered a well-balanced approach to eating for the general public. It is now recommended by the US Department of Agriculture (USDA) as an ideal eating plan for all Americans.
Major Risk Factors for Heart Disease That Cannot be Changed Age
Approximately 55% of all heart attack occur in people who are 65 years of age or older. This age group accounts for more than 80% of the fatal heart attacks.
Until recently, the incidence of coronary heart disease among women has been largely unexplored. Men have been the primary subjects in the coronary heart disease and risk factor studies because of the high incidence of both among men. However, coronary heart disease is also the leading cause of death and disability among women, accounting for almost 250,000 deaths annually. Women have less heart disease than men, particularly before menopause. The reasons for the difference include the following :(1) the female hormone estrogen protects the coronary arteries from atherosclerosis and (2) women have higher circulating levels of high-density lipoprotein (HDL) cholesterol, which also protects the arteries. After menopause, though, the heart attack rate among women increases significantly until the mid-60s, when women's risk is equal to that of men the same age.
Symptoms of meningitis in adults Are you looking for symptoms of meningitis in adults?
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs. Meningitis can be life-threatening because of the inflammation's proximity to the brain and spinal cord; therefore the condition is classified as a medical emergency.
Many of the bacteria and viruses that cause meningitis are fairly common and associated with other routine illnesses. Bacteria and viruses that infect the skin, urinary system, gastrointestinal or respiratory tract can spread by the bloodstream to the meninges through cerebrospinal fluid, the fluid that circulates in and around the spinal cord.
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.
The effect of Monosodium Glutamate The effect of monosodium glutamate on the apoptosis
of rat thymocytes and Bcl-2 protein expression
Voja Pavlović, Snežana Cekić
Arch Med Sci 2006; 2, 1: 28-31
Introduction: Monosodium glutamate (MSG) is the sodium salt of glutamic acid
widely spread in modern nutrition. Numerous recent studies have shown the
existance of glutamic receptors on different non-neuronal cells, which among
others also include lymphocytes and thymocytes. However, it has not yet been
precisely established what modulatory effect is created by the activation of these
receptors on the immune system cells.
Cosmetic Plastic Surgery Facts When you hear of cosmetic plastic surgery, what do you think of? A Hollywood star trying to delay the effects of aging? People who want to change the size of their stomachs, breasts, or other body parts because they see it done so easily on TV? Here is some facts about Cosmetic Plastic Surgery
Common Ankle Problems The primary care physician will often be the first to evaluate common foot and ankle problems. The patient's complaints will range from acute traumatic injuries to chronic conditions, which have progressed in severity.
The recognition of local and systemic factors that contribute to the patient's condition in conjunction with a thorough history and physical examination will direct the initial plan of management, the use of further diagnostic testing and the necessity of an Orthopaedic referral.
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.
Calculate bmi for teenage girls Calculate Your Body Mass Index
Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.