1. THE COMPOSITION OF BLOOD

3. The blood is really the transport system of the body, as it carries materials from one organ to another. It takes oxygen from the lungs to the heart and then to the working muscles. It takes carbon dioxide from the working muscles to the heart and then to the lungs. It also takes soluble food from the intestines and waste products from the kidneys.

4. What are the 4 main components of blood ? 1. RED BLOOD CELLS- The pigment that gives the cells their colour is called HAEMOGLOBIN and it attracts OXYGEN. It picks up oxygen in the lungs and delivers it to the working muscles. One cubic millimetre of healthy blood contains about 5 million red blood cells ( this is known as the “BLOOD COUNT” ).

7. People who live in mountainous or high altitude regions, where there is less oxygen in the air, have a higher BLOOD COUNT because the blood has to be extra efficient at picking up oxygen. People who live in these regions may have as much as 2 or more litres of blood. Athletes from these areas often do exceptionally well in distance races. CAN YOU GIVE ANY EXAMPLES ?

9. Other athletes go to train in these areas in order to improve their ability to cope better when they return to lower levels for competition. A controversial and illegal procedure called BLOOD DOPING is sometimes used which makes use of this knowledge. WHAT IS BLOOD DOPING ?

12. Red blood cells are made from red bone marrow. Where is the bone marrow again???

13. 2. PLASMA- A pale straw coloured liquid consisting of 90% water.

15. 3. WHITE BLOOD CELLS- These have an important function as the defence system of the body.

18. 4. BLOOD PLATELETS- Formed in the red bone marrow and helps in the clotting of blood.

24. SUMMARY:-

26. REVISION