DO YOU KNOW?

THE BLOOD

The blood is composed of red blood cells, white blood cells, platelets and the plasma. The red blood cells are red in colour and have a biconcave discs shape. It has no nucleus. Blood cells are formed in the bone marrow and have a lifespan of about 120 days. They are then destroyed by the liver and spleen. Its main function are to transport oxygen throughout the body, and picks up carbon dioxide in the body. This is done by the haemoglobin in the blood which becomes bright red when it is combined with oxygen in the lungs. Iron is an important element needed to build haemoglobin in the body. The white blood cells defend the body against disease that is caused by bacteria and other microorganisms. They attack the microorganisms by eating or destroying them by releasing antibodies. The platelets help to initiate the information of blood clots and breaks in broken blood vessels. They arise from the cells in the bone marrow that are released in small sections into the blood circulation. The blood plasma contains mainly water, amino acids, proteins, carbohydrates,lipids,vitamins, hormones, electrolytes and cellular waste. It is the liquid portion of the blood. 92% of it is water that transports nutrients, gases, vitamins, maintain fluid and electrolyte balance. It contains plasma proteins made in the liver, maintains the blood pressure and helps to transport food materials such as fats and vitamins. One of its proteins called fibrinogen is important for blood clotting when the blood vessels are injured.