1. Why is blood important? What is it made of?

2. Role of Blood Transport gases around the body (oxygen and carbon dioxide) Transport nutrients (i.e. Glucose) around the body

3. Red Blood Cell Red blood cells have a perfect biconcave shape for absorbing and releasing oxygen. Red blood cells are red only because they contain a protein chemical called haemoglobin which is bright red in colour. Haemoglobin contains the element Iron, making it an excellent vehicle for transporting oxygen. They also have no nucleus so they can transport as much oxygen as possible.

4. There are approximately five million red blood cells per cubic millimetre of blood, slightly more in men and less in women. The number of red blood cells is higher in people who live at high altitudes. Red blood cells do not have nuclei.

5. Haemoglobin Haemoglobin is an amazing chemical because if you warm it slightly and add a bit of acid, it will give up all its oxygen. As blood passes through the lungs, oxygen molecules attach to the haemoglobin. As the blood passes through the body's tissue, the haemoglobin releases the oxygen to the cells.

6. White Blood Cells There are usually a few thousand white blood cells per cubic millimetre of blood. Their jobs are to produce antibodies and to engulf bacteria, i.e. they fight disease. The engulf bacteria using a process called phagocytosis.

7. Plasma Plasma is the liquid part of blood. It contains many important substances which must be carried around the body.  Products of Digestion (Glucose)  Carbon Dioxide  Hormones  Vitamins The plasma is a slightly yellowish in colour.

8. Platelets To stop the loss of blood from wounds. Platelets form a clot which dries up into a scab. This is quite a good thing because it prevents any more blood from getting out and it prevents germs from getting in.

10. Components of Blood red blood cells -transport of oxygen white blood cells -defence plasma -transport of food/waste platelets -blood clotting