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Describe The Journey Of The Components Of The Blood From The Bone Marrow To Their Final Resting Place.

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Sheena Shah Describe The Journey Of The Components Of The Blood From The Bone Marrow To Their Final Resting Place. The heart is the organ that pumps blood around the body and never stops beating. Blood has four main components, red blood cells, white blood cells, platlets and plasma, which travel around the body. Blood cells originate from the stem cells in the bone marrow found in cavities within the flat bones such as the ribs and breastbone, by the process of haemopoieses. It then produces the lymphocytes, platlets and leucocytes. Blood travels through the body in double circulation. The first part is pulmonary circulation, where it flows from the heart to the lungs. The second part is called systemic circulation, where blood flows from the heart to the rest of the body. The heart has four chambers. The right hand side of the heart receives deoxygenated blood from the body and pumps it to the lungs. At the lungs, the blood gains oxygen, but loses pressure. ...read more.


Their function is to transport the respiratory gases oxygen and carbon dioxide around the body. The red colour of the erythrocytes is due to the presence of the haemoglobin pigment, which also carries the oxygen. The typical lifespan of the red blood cell is 90-120 days, before they are removed in the liver and spleen by macrophages. "The spleen filters the blood looking for foreign cells and old red blood cells that are in need of replacement. If a person does not have a spleen, they would get sick more often than someone with a spleen." (www.howstuffworks.com) Platlets are not true cells but are fragments of cells called megakaryocytes. They are involved in blood clotting. They disintegrate to release thromboplasts, otherwise they survive on an average of 10 days, when they are removed by the liver and spleen. Leucocytes are white blood cells. They help fight infections and aid in the immune process. Types of white blood cells include Lymphocytes, Monocytes and Granulocytes. Granulocytes comprise of Neutrophils, Eosinophils and Basophils. All white blood cells start in the bone marrow as stem cells. ...read more.


Once they are in the bloodstream Neutrophils can move through capillary walls into tissue. They are attracted to unknown material, inflammation and bacteria. For example, if a person gets a splinter or a cut, Neutrophils will be attracted by a process called Chemotaxis. Chemotaxis lets motile cells move toward higher concentrations of a chemical. Once a Neutrophil finds a foreign particle or bacteria, it will engulf it, releasing enzymes from its granules to kill the bacteria. When Neutrophils die they form pus and other cellular debris. Eosinophils have a double lobed nucleus and granules. They help control the allergic response. Their numbers increase during allergic reactions and in response to some parasitic infections. Basophils have an s-shaped nucleus and secrete large amounts of histamine, which increases inflammation, this helps to keep a balance between blood clotting and not blood clotting. Blood circulation around the body is continuous and is vital as it provides the body with oxygen so that muscles and organs are able to work. Eventually the components of the blood are used up for protection against bacteria, removed by the liver and spleen or die. ...read more.

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