what's lymphocyte and what is immune system specifically?
611521
A lymphocyte is a type of white blood cell involved in the human body's immune system. There are two broad categories of lymphocytes, namely T cells and B cells. Lymphocytes play an important and integral part of the body's defenses.\n\nT cells are chiefly responsible for cell-mediated immunity whereas B cells are primarily responsible for humoral immunity (relating to antibodies). T cells are named such because these lymphocytes mature in the thymus; B cells, named for the bursa of Fabricius in which they mature in bird species, are thought to mature in the bone marrow in humans.\n\nIn the presence of an antigen, B cells can become much more metabolically active and differentiate into plasma cells, which secrete large quantities of antibodies.\n\nMicroscopically, in a Wright's stained peripheral blood smear, a normal lymphocyte has a large, dark-staining nucleus with little to no basophilic cytoplasm. In normal situations, the coarse, dense nucleus of a lymphocyte is approximately the size of a red blood cell (about 7 micrometres in diameter). Some lymphocytes show a clear perinuclear zone (or halo) around the nucleus or could exhibit a small clear zone to one side of the nucleus.\n\nIt is impossible to distinguish between T cells and B cells in a peripheral blood smear. Normally, flow cytometry testing is used for specific lymphocyte population counts. When one must specifically determine the percentage of lymphocytes that produce a particular secretion (say, a specific antibody or cytokine), the ELISPOT or secretion assay techniques can be used instead.\n\nThe human immunodeficiency virus (HIV) hijacks and destroys T cells (specifically, CD4+ lymphocytes). Without this key defense, the body is susceptible to opportunistic diseases that otherwise would not kill healthy people.\n\nA lymphocyte count is part of a peripheral complete blood cell count and is expressed as percentage of lymphocytes to total white blood cells counted. An increase in lymphocytes is usually a sign of a viral infection (in some rare cases, leukemias are found through an abnormally raised lymphocyte count in an otherwise normal person). A general increase in the number of lymphocytes is known as lymphocytosis whereas a decrease is lymphocytopenia.\n\nThe formation of lymphocytes is known as lymphopoiesis.\n\n\nThe immune system is the system of specialized cells and organs that protect an organism from outside biological influences. (Though in a broad sense, almost every organ has a protective function — for example, the tight seal of the skin or the acidic environment of the stomach.) When the immune system is functioning properly, it protects the body against bacteria and viral infections, destroying cancer cells and foreign substances. If the immune system weakens, its ability to defend the body also weakens, allowing pathogens, including viruses that cause common colds and flu, to grow and flourish in the body. The immune system also performs surveillance of tumor cells, and immune suppression has been reported to increase the risk of certain types of cancer
1083478
Intracellular immune respond is the respond that occur in the cell while extracellular respond occur outside the cell. For example the immune respond of Amoeba is Intracellular while that of Mammal is Extracellular.
400670
Innate immunity: defence mechanisms that are non-specific and ubiquitous. Think of it as the cannon fodder of the human immune system. These are the cells that are often first on the scene, and charge in blindly, attacking everything left, right and center, and then die. Kind of like suicide bombers. Only good.\n  Includes cells such as neutrophils, monocytes, macrophages, dendritic cells, and very importantly, the entire complement system.\n\n------\n\nAquired immunity: also called adaptive immunity, comes from exposure to immunogens.\n  Includes B cells and T cells. B cells make antibodies after being exposed to an immunogen. Encountering that foregin body again (now called an "antigen") will cause the adaptive immune system to react faster than it did previous (because it has this antibody memory, now. Thats why its adaptive, or aquired).
601144
White Blood Cells\n\nThere are between 6,000 and 8,000 white cells per cubic millimetre of blood. White cells, slightly larger than red cells, are also called leukocytes. They purify and protect the body from infections. Once an infection is detected in any part of the body, the while cells move in to fight it.
190065
Blood is composed of 6 different kinds of cells (red blood cells and 5 types of white blood cells) and platelets, which are just pieces of cells.\nIn a normal person, there is an average, normal number of each kind of cell.  The numbers of the cells can increase, and (appear to) decrease if the person is sick.\nFor example, if someone has a high neutrophil count then it is suggestive of a bacterial infection or tissue damage.  This is because neutrophils ingest and destroy bacteria and dead tissue.  They're the "clean-up" cells.\nAn increase in lymphocytes indicates a viral infection because lymphocytes fight in cellular immunity.  Meaning that they kill cells that are infected/infectious.\nEosinophils are increased in allergies and parasitic infections (which stimulate allergic reactions).  Their function is to limit the damage done by basophils.  Basophils release histamine (makes your nose run and eyes water) and heparin (which makes your blood not clot).\nMonocytes are also clean up cells and right now I can't remember why they are increased - sorry.\nRed blood cells are the most abundant.  Their main function is to provide all of the tissues of the body with oxygen.  There's lots of tissues and they need lots of oxygen, so there's lots of red blood cells.\n\nI'm not taking into account diseases like lymphomas, leukemias, and polycythemia.  These are disease in which some blood cells are increased because the mechanism that controls their amounts has gone wonky and has nothing to do with the function of the cells.\n\nI hope this explaination helps - and is clear enough to understand.
212688
Plasma is a part of your blood. Blood consists of red cells, plasma & platelets. The plasma is comparable to gravy. Lymph is a system in your body that is part of your immune system. Physical movement causes the bones/muscles to move which then exerts influence on the lymph system, making it flush. It helps remove toxins from the body.
461831
Humoral immunity refers to an immune response from antibodies (for example, an antibody is produced by a B cell and recognizes a foreign antigen and triggers an immune reponse).  In contrast, cell mediated immunity occurs when a cell (for example a T cell) directly recognizes a foreign antigen being "presented" by another cell.
922230
There are also different branches of the immune system, innate and adaptive, also known as non-specific and specific immunity respectively.  \n\nThe innate, non-specific defense system can be compared to the basic principles of defense, i.e. find the person with the ball, and tackle him.  There is no specificity, every cell/player does the same thing.  \n\nThe adaptive/specific arm of the immune system can be paralleled to the designed parts of a defensive play, i.e. every player covers a SPECIFIC person, and has a specific task.
373312
As blood is sent through the capillaries, some of it is filtered through the epithelial wall into the interstitial spaces around the cells in tissues.  This fluid is slowly forced into small little vessels called lymph vessels.  Lymph is the best way of finding out if there are bacteria, virus (pathogens) or even allergens/antigens in the tissues.  The lymph eventually drains into lymph nodes which are major sites for immune system communication. As fluid enters, some is pushed out.  These lymph vessels continue to merge until they become a major lymph vessel that drains in the subclavian vein.  This merges with the vena cava and thus returned to blood circulation.
593569
lymphatic system _ blood,white blood cells\nrespiratory system - lungs\nreproductive system - penis/vagina\ncardiovascular system _ heart, blood\nskeletal system - skeleton\ndigestive system - stomach, intestines\nnervous system - brain\nendocrine sytem - homones, glands\netc.
918675
the main part of specific immune system is Tcell and Bcell...it's hard to explain in details but i try to sum up,when the antigen enters the bode Tcell works a APC and receives antigene parts by MHC on it,MHC stimulate the Tcell to produce IL and INF and these stimulate Bcells to produce specific antibodies against Ag...some of these antibodies destroy the Ag by stimulating the complements and other parts of immune system and some Bcells convert to memory cells for the next time
132322
Bone marrow is the tissue that produces the very immune system cells that attack transplanted organs. Since bone marrow is a transplant, it will not attack itself, since it recognizes its own cells. Therefore, bone marrow is not rejected. Sometimes, however, the immune system cells that transplanted bone marrow produces may not recognize host tissues (since they "look" foreign to them) and may start attacking them. In a sense, the transplant "rejects" the host. This phenomenon is called graft-versus-host disease.
650599
Cell-Mediated Immunity\nIndex to this page \nDelayed-Type Hypersensitivity (DTH) \nContact Sensitivity \nKilling intracellular parasites \nAnti-Viral Immunity \nGraft Rejection \nGraft-versus-host disease \n \nThe human body can respond to antigen in many different ways. These fall into two major categories: \nantibody-mediated immunity. Antibodies, dissolved in blood, lymph, and other body fluids bind the antigen and trigger a response to it. (This form of immunity is also called humoral immunity.) Discussion of antibodies \n\ncell-mediated immunity (CMI). T cells (lymphocytes) bind to the surface of other cells that display the antigen and trigger a response. The response may involve\nother lymphocytes and \nany of the other white blood cells (leukocytes)
386051
erythrocytes (red blood cells)\n\nneutrophil granulocytes (the most abundant type of white blood cells and form an integral part of the immune system)\n\neosinophil granulocytes (white blood cells that are responsible for combating infection by parasites in the body)\n\nlymphocytes (a type of white blood cell involved in the human body's immune system that plays an important and integral part of the body's defenses)\n\nthrombocytes (are the blood cell fragments that are involved in the cellular mechanisms that lead to the formation of blood clots)\n\nother blood components: fluid plasma
452496
Humoral immunity is mediated by antibodies, which are made by B lymphocytes, when they mature to be plasma cells.\n\nCell mediated immunity involves T lymphocytes of various kinds.\n\nActually, AFAICR, T lymphocytes play a role in the very early stages of initiating Humoral immunity to a new antigen; they do the control and liaison work, via cytokines (lymphokines.)
597481
Briefly, the immune system scours the organism for what appear to be foreign invaders.  When it goes haywire, we now have an autoimmune disease -- rheumatoid arthritis, MS, poly myalgia rheumatic,and of course many others.  Interestingly, as sperm develop, the immune system does not attack the sperm, though they are in essence a different type of organism within the body.S[perm cells are guarded by what is commonly called a "nurse" cell.  As well it is interesting that the body does not attach a growing fetus -- usually -- (When it does, it is generally an rH problem).  In essence there is no "interrelationship".  The immune system is tolerent, at times to what appears a foreign living thing,(sperm) and intolerant at times to the body in which it is housed.(rheumatoid arthritis in which the immune system attacks its own cartlidge.) { Heart transplants, and other organ transplants can only succeed if the immune system is weakened.  Transplants would be immediately attacked otherwise.  And interestingly, weakened immume systems in the end, open us all up to cancer.  We all have cancereous cells in us  at all times -- normal cells that have become malignant.  The immune system recongnizes them and eliminates them.  Those with weakened immune systems are more prone to cancer.}  Maybe more information that you wanted to know....?
110574
The thymus is an organ in the chest, under the breastbone. It produces immune cells called T cells and is important in their maturation. The thymus is critical for the development of the immune system of infants. It has important functions in adult immunity, but adults can live without a thymus.