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.
Candida albicans Causes, Those at Risk, Symptoms and Treatment Candida albicans is a fungus that is normally present on the skin and on membranes of the mouth, throat, intestines, and vagina. It becomes an infecting agent only when there is some change in the body environment that allows it to grow out of control.
non Hodgkin lymphoma Symptoms Definition of non-Hodgkin lymphoma: Any of a large group of cancers of lymphocytes (white blood cells). Non-Hodgkin lymphomas can occur at any age and are often marked by lymph nodes that are larger than normal, fever, and weight loss. There are many different types of non-Hodgkin lymphoma. These types can be divided into aggressive (fast-growing) and indolent (slow-growing) types, and they can be formed from either B-cells or T-cells. B-cell non-Hodgkin lymphomas include Burkitt lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma, follicular lymphoma, immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, and mantle cell lymphoma.
Best Baby Formula Brand Do you looking for best baby formula brand? here is some good article about best baby formula.
When youâ€™re deciding which formula is right for your baby, you will need to take several factors into consideration. Think about her health and dietary needs, her age, and the cost and preparation time of different formula milks. Our guide to formula milks will help you to choose the right type for your baby.
What is Asthma Symptoms and Treatment What is asthma? what is asthma symptoms and how treatment for asthma?
When we talk about bronchial hyper-responsiveness, what we are saying is the following: If you take an individual without asthma and you challenge that individual with an asthma provoking substance, methacholine, you can see that no matter how much you increase methacholine, there is no major change in air flow. However, if the individual does have bronchial hyper-responsiveness, various degrees of methacholine can cause that air flow to drop 20%. And any drop will tell you the degree of responsiveness and it will then tell you the degree of severity of the disease. This is what we are talking about when we talk about bronchial hyper-responsiveness.
From the point of view of what is bronchial hyper-responsiveness, regardless of the stimulus which is often not an allergy, a number of cells have turned on, which causes a disruption in the bronchial mucosa. It is this disruption that makes the airway hyper-reactive. Well, as I mentioned, despite the fact that you have some homogeneity about inflammation and some homogeneity about bronchial hyperactivity, there is a tremendous heterogeneity in symptoms. Fifteen to 20% will cough. Or they can cough and or wheeze and they can be short of breath, associated with chest tightness. So the disease can reflect itself in many different ways.
Kidney Stones Causes, Symptoms and Treatment Kidney stones are deposits of mineral or organic substances that form in the kidneys. When abnormally high levels of certain minerals, such as calcium, are in the urine, they may condense into hard masses, forming stones in the kidney or urinary tract. The stones may be as small as a tiny pebble or as large as a walnut.
Best cold medicine for adult What is the Best cold medicine for adult?
Cold medicine can be a help and a hindrance in our lives when we are sick. Though it won't cure your cold or flu, it can improve your symptoms. But it also can have side effects. Also, which one do you choose? It can be quite confusing. Here you will find out about different cold medicines, how they work, examples of different products in each category and what they are used for.
Naproxen Side Effects 500mg Long Term Naproxen is in a group of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). It works by reducing hormones that cause inflammation and pain in the body.
Early Onset Dementia Symptoms Are you looking for early onset dementia symptoms? Familial Alzheimer's disease (FAD) or Early onset Familial Alzheimer's disease (EOFAD) is an uncommon form of Alzheimer's disease that usually strikes earlier in life, defined as before the age of 65 (usually between 50 and 65 years of age, but can be as early as 15) and is inherited in an autosomal dominant fashion, identified by genetics and other characteristics such as the age of onset. It accounts for approximately half the cases of early-onset Alzheimer's disease. Familial AD requires the patient to have at least one first degree relative with a history of AD. Non-familial cases of AD are referred to as "sporadic" AD, where genetic risk factors are minor or unclear.
Food Borne Illness Prevention Most of us have experienced the characteristic symptoms of diarrhea, nausea, cramping, and vomiting that prompt us to say, “It must be something I ate.” The number of cases of food poisoning in the United States has been growing (there are three millions of cases per year), which has prompted the Food and Drug Administration to make prevention of food contamination a high priority. Deaths in Pacific Northwest in 1994 attributed to consumption of Jack-in-the-Box hamburgers contaminated with Escherichia coli, a bacterial agent, increased people’s fears about the overall safety of meat, poultry and seafood.
Fiber foods functions and consumption rule The role fiber plays in promoting nutrition and health has been a controversial subject in recent years. What exactly is fiber? How effective is it in reducing certain health risks? Are certain types of fibers more effective than others?
Fiber, often referred to as “bulk” or “roughage”, is the indigestible portion of plant foods that helps move foods through the digestive system and softens stools by absorbing water. Insoluble fiber, which is found in brain, wholegrain breads and cereals, and most fruits and vegetables, is associated with these gastrointestinal benefits and has also been found to reduce the risk for several forms of cancer. Soluble fiber appears to be a factor in lowering blood cholesterol levels, thereby reducing risk for cardiovascular disease. Major sources of soluble fiber in the diet include oat bran, dried beans (such as kidney, garbanzo, pinto, and navy beans), and some fruits and vegetables.
Cochlear Implant Cost Are you looking for Cochlear Implant Cost? A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. The cochlear implant is often referred to as a bionic ear.
As of April 2009, approximately 188,000 people worldwide had received cochlear implants; in the United States, about 40,000 adults and over 30,000 children are recipients. The vast majority are in developed countries due to the high cost of the device, surgery and post-implantation therapy. A small but growing segment of recipients have bilateral implants (one implant in each cochlea).
Naegleria fowleri symptoms Are you looking for Naegleria fowleri symptoms? Naegleria is a microscopic ameba (single-celled living organism) that can cause a very rare, but severe, infection of the brain. The ameba is commonly found in warm freshwater (for example, lakes, rivers, and hot springs) and soil. Only one species (type) of Naegleria infects people: Naegleria fowleri.
Codeine Cough Syrup and Side Effects Cough syrup with codeine
You have a hacking cough.Your chest hurts and your coughing is keeping you up at night. The over-the-counter cough drops and syrups are not doing it for you.As much as you hate going to see the doctor, you reluctantly decide that it is time to take a trip.The nurse takes your weight, takes your temperature, and takes your blood pressure.