Organs and Tissues
The immune system has many different organs, cells and tissues that work together to keep our body healthy. These organs are called lymphoid organs because they are home to lymphocytes; white blood cells.
Spleen
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The spleen is an immune organ about the size of a fist. It is located in the adominal cavity, cupping the upper left side of the stomach. The spleen is also the largest organ in the immune system. This organ contains special compartments where immune cells gather and work.The spleen is abundant with several kinds of white blood cells and red blood cells too. It has two primary functions: to filter the blood and to coordinate the immune response. The spleen is made up of two different tissues, the red and white pulps, each of which serves one of these functions. The red pulp serves for filteration. Many blood vessels flow through the spleen, from the splenic artery which divides into smaller and smaller branches.This is to guarantee all the blood in the body is cleaned. It removes pathogens and other foreign matter. The white blood cells also remove old red blood cells and other cellular deberis.The white pulp is found in little clumps inside the red pulp. It is made up of lymphoid tissue. The white plups purpose is to make and mature immune cells and blood cells. In addittion to making and maturing immune cells, antibodies are often made by lymphocytes in the white pulp.The spleen also helps fight certain kinds of bacteria that cause pneumonia and meningitis.
Thymus
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The thymus or thymus gland is located in the middle of the chest, near the heart behind the beast bone. This is where t-lymphocytes or t-cells develop, the t stands for thymus. These unmatureT-cells are produced in the bone marrow, but migrate to the thymus where they stay untill they are fully developed into either helper t-cells or cytotoxic t-cells. The t-cells must develop in the thymus or they will not properly work later on. As a person gets older the thymus begins to shrink and become less active because most of the t-cells move out of the thymus to the bloodstream and other parts of the body.
Bone Marrow
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Bone Marrow is the soft, fattie tissue in the hollow centre of bones. It is the ultimate source of all blood cells, including lymphocytes. All these cells are produced within the bone marrow by speacial cells called stem cells. The process in which these cells form from is called Hematopoiesis. During hemstopoiesis stem cells adapt in to one of two things. Either mature cells of the immune system or forerunners of cells which then migrate out of the bone marrow to another part of the body to finish maturing. Bone marrow produces cells such as B-cells,platelets and red blood cells.
Adenoids
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The adenoids are two gland made of soft tissue called lymphoid tissue, they are part of the immune system. They are located behind the nasal cavity in the upper back of the nasal passage. White blood cells circulate through the adenoids and react to foreign invaders that have entered the body, by trapping the bacteria or viruses you have breathed in. They also help by preventing throat and lung infections like the tonsils. Adenoids get bigger after you are born, but usually stop growing between the ages of three to seven years old. By adolesence our adenoids begin to shrink and by adulthood most people's are completly gone. Some people's adenoids may become enlarged or swollen. This can cause trouble breathing through the nose, snoring and disruption of sleep at night and a constatly runny nose. Because of these symptons people may chose to remove their adenoids. Even though they prevent a lot of infections they are not considered important.
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Tonsils
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The tonsils are immune organs located at the back of the throat. There are two tonsils, one on either side at the back of the throat. They stop swallowed and inhaled harmful substances from getting father into the body.In response to an attack on the body from a foreign substance the tonsils can become inflamed as an immune system response.Tonsils trap bacteria and viruses you may breath in. White blood cells inhabit the tonsils and help to kill germs and help prevent infection in the throat and lungs.Tonsils are made of soft glandular tissue and are part of the immune system.
Tonsils are visable when you opening your mouth wide and look in a mirror. They are the two fleshy lumps that you can see at the sides and back of the mouth. Tonsils can be effected by tonsilitis and infectious mononucleosis, tonsils may need to be removed because of these conditions.
Tonsils are visable when you opening your mouth wide and look in a mirror. They are the two fleshy lumps that you can see at the sides and back of the mouth. Tonsils can be effected by tonsilitis and infectious mononucleosis, tonsils may need to be removed because of these conditions.
Lymph Nodes
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Lymph nodes are small immune organs about the size of a pea or kidney bean. They are made from lymphoid tissue and contain spealized structures such as Germinal centre, follicle, medulla, cortex and paracortex are just a few. Lymph nodes are home to thousands of white blood cells. Hundereds of lymph nodes are throught the body, spaced along a network of tubes called lymph vessles. These organs collect a fluid called lymph that leaks out of bloodvessels. This fluid called lymph travels along lymph vessels and through lymph nodes. Where it is cleaned by the white blood cells that reside there. Then it rejoins the blood in the bloodstream, through large bloodvessels near the heart.
Appendix
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The appendix is a small, slender pouch, about two to four inches long. It is located near the of the large and small intestines. The exact function of the appendix in humans is unknown and has been debated on, some scientists believe that the appendix is a "safe house" or storge area for good bacteria that lives in the intestines.Also the appendix does contain lymphoid tissue. The appendix can be removed if neassisary without effects or damage to the immune system. For example if someone's appendix bursts and they have to get it removed, it won't effect anything.
Peyer's patches
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Peyer's patches are round or ovoid bundles of lymphoid tissue, they are similar to lymph nodes. They are made up of unencapsulated lymphatic cells They are located in the mucosa and extending into the submucosa of the small intestine, especially the ileum. Peyer's patches protect the mucous membranes of the small intestines from infection. These peyer's patches contain B-cells and T-cells, so they can protect the intestine interior if an infection occurs.
Lymphoid Tissue
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Lymphoid tissue is a specialized form of reticular connective tissue.Lymphoid tissue is defined as being loose, dense, or nodular. Most of the body's immune system organs are made of lymphoid tissue. It is important in the immune system it helps protect it from infection and foreign matter. Lymphoid tissue is present throughout the body, this includes the immune organs lymph nodes, the spleen, tonsils, adenoids, and other immune organs and structures.