B7.2

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  • Created by: keeels
  • Created on: 15-06-13 16:54
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  • B7.2
    • Blood
      • Plasma - Pale, yellow liquid made up of mainly water. It transports a wide range of materials including nutrients such as glucose, antibodies, hormones and waste
        • Red blood cells - transport oxygen and are; packed with haemoglobin,have no nucleus, and have a bioconcave shape.
          • Haemoglobin binds oxygen as blood passes through the lungs . The oxygen is released from haemoglobin as blood circulates through the tissues of the body.
          • Having no nucleus allows for more space for haemoglobin
          • The bioconcave shape gives the cells a large surface area, making diffusion of gases very efficient, the shape also gives cells flexibility to squeeze through tiny capillaries
        • white blood cells - fight infection from disease causing microorganisms. They produce antibodies and engulf and digest microorganisms by PHAGOCYTOSIS.
        • Platelets - are fragments of cells that are made from the cytoplasm of large cells. They stick to the edge of cuts and will send out chemicals that trigger a series of reactions that form a clot at the cut site. clotting helps  to stop too much blood being lost from the body.
    • Double circulation
      • Our blood is pumped around in two separate loops: around the body and around the lungs.
      • Each side of the heart has two chambers- an ATRIUM and a VENTRICLE
        • Blood from the body enters the right atrium of the heart. It is pumped out of the right ventricle towards the lungs to pick up oxygen. The blood becomes OXYGENATED.
          • It returns to the left atrium and passes into the left ventricle. It gets another harder pump which carries it  around the rest of the body. The left ventricle has a thicker wall of muscle than the right , because it has to pump blood to the whole of the body. The right ventricle only has to pump to the lungs.
            • As the blood passes around the body it gradually gives up its oxygen to the cells. It becomes DEOXYGENATED. The blood then returns to the right atrium again. So blood passes through the heart twice on every circuit of the body.
      • The heart
        • Pulmonary artery - The artery that carries deoxygenated blood to the lungs. The artery leaves the right ventricle of the heart
        • Pulmonary vein - the vein that carries oxygenated blood from the lungs to the left atrium of the heart.
        • Vena cava : main vein from body
        • Right side of heart has less oxygen than left.
        • Aorta - The main artery that carries deoxygenated blood away from the left ventricle of the heart.
    • Valves and tissue fluid.
      • Valves stop blood going backwards. They act like one way doors to keep the blood flowing in one direction.
        • Between each atrium and ventricle - These valves stop blood flowing backwards from the ventricle into the atria
        • Between the ventricles and the arteries leaving the heart- these stop valves flowing backwards from the arteries into the ventricles.
        • Valves are also found in the veins. Blood pressure is lower in veins than in arteries. Valves stop blood flowing backwards in the veins in between each pump of the heart
      • Capillary bed - large number of narrow blood vessels that pass through each organ of the body. capillaries receive blood from arteries and return it to veins. capillary walls are only one cell thick.
        • Capillaries are where chemicals in the body's cells and in the blood are exchanged. The structure makes them ideally suited for this function.
      • Tissue fluid - plasma that is forced out of the blood as it passes through a capillary network.Tissue fluid carries dissolved chemicals from the blood to cells.

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