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.
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.
Talking with Your Doctor about Cancer Diagnosis Anytime there is suspicion of cancer, the person involved is likely to react with great anxiety, fear, and anger. Emotional distress is sometimes so intense that the person involved is unable to severe as his or he own best advocate in making critical health-care decisions. If you find it difficult to know what to ask your doctor on a routine exam, imagine how hard it would be to discuss life or death options for yourself or loved one. Having a list of important questions to ask when you appear at the doctor’s office may help tremendously. Remember, your health-care provider should be your partner in making the best decisions for you. By actively challenging, questioning, and letting the physician know your wishes, difficult decisions may become easier.
Infantile Eczema (Atopic Dermatitis) Skin eruptions which my occur at any time in life but which usually are found in infants and children may be aczema. The condition at first appears on the face and on the back of the wrists. Later in childhood it may be found in the bends of the elbows and the region back of the knees. At a result of scratching, these break open and oozing takes place. There is severe itchiness, and this constitutes the most disturbing feature of the disease. Allergic factors play a rather important role in this dermatitis. Most of these people have a family history allergy. They may present other allergic manisfestations, such as hay fever or asthma. Indeed, in some instances it is realized that the infant or child cannot tolerate certain foods or sensitive to certain substances in his environment.
Progeria Information and Facts Are you looking for progeria information and facts? here is some information about progeria.
Progeria is an extremely rare genetic condition wherein symptoms resembling aspects of aging are manifested at an early age. The word Progeria comes from the Greek words "pro" means "before" and "géras" means "old age". The disorder has very low incidences and occurs in an estimated 1 per 8 million live births. Those born with progeria typically live to their mid teens and early twenties. It is a genetic condition that occurs as a new mutation (de novo), and is not inherited. Although the term progeria applies strictly speaking to all diseases characterized by premature aging symptoms, and is often used as such, it is often applied specifically in reference to Hutchinson-Gilford Progeria Syndrome.
Ovarian Cancer Staging and Treatment Are you looking for article about ovarian cancer staging and treatment? Here is good stuff about ovarian cancer staging and treatment.
The FIGO staging classification scheme for ovarian cancer is outlined in the box, page 42. The staging of advanced disease (spread throughout the abdomen) may be obvious to most physicians, but it is important for a surgeon to be meticulous in the staging of early ovarian cancer. In one study it was found that one third of patients referred with stage I or stage II disease were actually found to have stage III disease when the appropriate staging operation was performed. Similar results have been reported by other researchers.
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.
Cellulitis Home Treatment Cellulitis is a common but potentially serious bacterial (streptococcus or staphylococcus) infection of the skin and underlying skin tissue. It mostly affects the lower legs, although it can occur anywhere on the body or face.
Menopause Definition, Age and Treatment Guidelines Elizabeth K. Stanford, MD
We all know what happens at a certain age to women. It is genetically determined that they stop making estrogen in their ovaries. That’s why fat people are overweight. Ladies are less likely to get hot flushes and less likely to get hip fractures, and more likely to get endometrial cancer. The follicles stop developing in the gonad at a certain age that is genetically predetermined. And actually before that phase happens, to end ovulation and menstrual cycle regularity and sometimes some psychologic symptoms. Of course the hot flush which occurs in about ¾ of women and it occurs without an aura. It just happens and frequently wakens them from sleep and is very disturbing. So these are the early symptoms of estrogen deficiency. A few years later the target tissues start to atrophy; the vagina and the urethra and the bladder, which are urologically grafted to the urogenital sinus. And since estrogen stimulates collagen synthesis, there is atrophy in the dermis of the skin. You’ve all noticed those vertical lines in the upper lip of women. That’s a sign of not making enough collagen or dermis.
When estrogen deficiency begins, there is an increased rate of bone resorption, which in about half of white women leads to osteoporosis and if they live long enough then they may develop fractures from this. These fractures start appearing about age 60. There is also an acceleration of cardiovascular disease in women not taking estrogen, and estrogen will retard the acceleration of atherosclerosis. Of course these are the serious problems that are asymptomatic. The osteoporosis and the atherosclerosis. So we don’t mention them until the event occurs. You all measure blood pressure and treat hypertension and you make a cholesterol to treat cardiovascular disease, and now there is a move afoot to measure bone mineral density in all white women and Asian women. And now found that even about 30% of blacks have osteoporosis, so this is being reimbursed by Medicare and this is something that you will be doing in the next few years.
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.
Gangrene Causes, Symptoms and Treatment Gangrene is a term that refers to the death of body tissue due to diminishment or loss of blood supply, leading to nutrient and oxygen deprivation. There are three major types of gangrene: moist, dry, and gas gangrene. Although gangrene usually affects extremities, it can sometimes affect the internal organs.
Apnea in children and adults Apnea is strictly defined as the absence of breathing. The term is also used to refer to an interruption in breathing that occurs in some premature babies and also during the sleep of some children and adults.
Apnea in infants
The usual cause of apnea in infants is immaturity of the brain centers that regulate breathing. From time to time, the infant suddenly stops breathing completely and turns blue. If the baby is stimulated in some way (for example, by a flick of the finger on the bottom of the foot), he or she will usually start breathing normally at once. Seldom is it necessary to use first-aid measures or a mechanical respirator to restart breathing. However, because a history of apnea is one of the factors that may be associated with sudden infant death syndrome (SIDS), physicians sometimes recommend monitoring high-risk infants with equipment that sounds an alarm if any stoppage of breathing is detected. In some cases, the tendency toward apnea disappears a few week after birth, when the breathing control centers have matured.
Tips for Getting Pregnant You have been married for years? but have not had children. Maybe it helps you practice the following tips for couples to get pregnant.
Ketogenic Diet Plan Menu Are you looking for Ketogenic Diet Plan Menu? The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. It is unrelated to the diets used for bodybuilding and weight-loss, which often involve much lower levels of ketones. The diet mimics aspects of starvation by forcing the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fuelling brain function. However, if there is very little carbohydrate in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.