2.2 Relate the structure of the red blood cell to its function.

The Red blood cell also known as Erythrocytes has many important roles to play in our body. The main function is to carry oxygen from the lungs to the tissue in your body and take the carbon dioxide from the tissues to the lungs so it can be breathed out. The structure of the RBC plays a key role in effective use as it is biconcave in shape this gives it the flexibility, because it is very flexible it means it can bend and twist through the blood vessels. Without the ability to flex they would get stuck and cause problems in your circulation. A RBC is tiny, only 1/25,000 of an inch in size and your blood contains 25 trillion, replacing them constantly. Red Blood cells are made in the red bone marrow and in adults can be produced in the thoracic bones, vertebrae, cranial bone and the ends of the femur and humorous bones. Red blood cells do not contain a nucleus, this means they cannot reproduce. After 120 days they are ingested by phagocytic cells in the liver and the spleen and then the body replaces them. Erythrocytes are known as red blood cells because of a substance called haemoglobin, haemoglobin are composed of simple protein and iron pigments and when combined with oxygen their colour becomes bright red.