1. LIFE PROCESSES
CIRCULATORY SYSTEM

2. Why is the Circulatory System important?

3. The circulatory system or cardiovascular system in humans is the combined function of the heart, blood and blood vessels to transport oxygen nutrients and oxygen to organs and tissues through out the body and carry away waste products.

4. The main parts of the circulatory system are
Blood – Red blood cells, white blood cells and platelets.
Blood vessels – Arteries, capillaries and veins.
Heart – Made of cardiac muscle

5. The Blood

6. Blood Plasma 55% liquid part of blood Blood Cells 45% Platelets
Red Blood Cells
White Blood Cells
Lymphocytes
Phagocytes
Antibodies

7. Plasma
Plasma is the liquid part of blood. It consists predominantly of water and salts. It also contains other small molecules including vitamins minerals and waste products.
Plasma is yellow in colour due to protiens dissolved in it.

9. Blood Cells

10. Red Blood Cells:
Red blood cells make up 45% of blood volume. The main function is to carry oxygen from the lungs to every cell in the body. Red blood cells are composed mostly of a protein and iron compound called hemoglobin.  

11. Haemoglobin has an affinity for oxygen i. e. A liking for oxygen
Haemoglobin has an affinity for oxygen i.e. A liking for oxygen. Red blood cells do not have a nucleus as a result they do not live for very long about three months

12. Red blood cells have a bi concave shape , this gives them a much larger surface area , as such the larger the surface area the more oxygen they can carry. Think of a doughnut but with the centre filled in .

14. White Blood Cells

15. There are two main types of white blood cells: Phagocytes and  lymphocytes. Lymphocytes are responsible for the production of antibodies which are produced in response to an infection. Phagocytes engulf bacteria and are also responsible for the removal of dead cells.

16. Lymphocytes recognise bacteria antibody made in response to bacteria.
Bacteria enters body
Antibody clings to bacteria, also causing bacteria to clump together.
Phagocytes recognize antibody and ingest bacteria by phagocytosis

17. Lymphocyte 
Scanning electron micrograph of a normal T lymphocyte. T lymphocytes are specialized white blood cells that identify and destroy invading organisms such as bacteria and viruses. Some T lymphocytes directly destroy invading organisms, whereas other T lymphocytes regulate the immune system by directing immune responses.

19. Macrophage Engulfing Bacterium
A macrophage, in yellow, engulfs and consumes a bacterium. Macrophages are large phagocytes, cells that wander through the body consuming foreign particles such as dust, asbestos particles, and bacteria. They help protect the body against infection.