1. BLOOD and CIRCULATION

2. Blood By the end of the lesson you should be able to:
State the composition of Blood
State the function of red blood cells and plasma
Explain the function of haemoglobin in the transport of oxygen
State the function of white blood cell

3. Blood the average human has 5 litres of blood
it is a transporting fluid
it carries vital substances to all parts of the body
Blood is thicker than water and has a bit of a salty taste.

4. The components of the blood
and their jobs

5. centrifuge

6. Blood Composition Plasma: Serum and Fibrin
Buffy Coat: White Blood Cells
Red Blood Cells

8. What is blood made up of? Red blood cells White blood cells Platelets
Plasma
Breakdown products of digestion, such as glucose, fatty acids and amino acids
Dissolved mineral salts
Carbon dioxide
Urea
hormones

9. Blood cells are created in the bone marrow, which is the sponge-like material in the center of bones.

10. Plasma

11. Plasma is the liquid part of the blood
Plasma transports – blood cells, soluble food molecules, waste products, hormones, antibodies, clotting proteins
Plasma is a straw-yellow coloured liquid
It makes about 55% of total blood volume
if everything in plasma was removed, plasma would look like this:

12. Red Blood Cells (RBCs / erythrocytes)

13. Red blood cells specialisations
1) biconcave shape
2) no nucleus
 extra space inside
3) contain haemoglobin
 the oxygen carrying molecule
 250million molecules / cell
4) It is the most abundant cell in the blood (40-45% total blood vol.
5) Survives an average of 120 days
increases the surface area so more oxygen can be carried

14. Haemoglobin gives red blood cells their colour
can carry up to 4 molecules of O2
associates and dissociates with O2
contains iron

15. Function of Haemoglobin
When there is a high concentration of oxygen e.g in the alveoli haemoglobin combines with oxygen to form oxyhaemoglobin. When the blood reaches the tissue which have a low concentration of oxygen the haemoglobin dissociates with the oxygen and the oxygen is released into body tissues

16. White blood cells
(WBC’s /Leukocytes)

17. Cells of the immune system involved in defending the body against both infectious disease and foreign agents –Body’s Defence mechanism
Much larger than the RBC’s
Fewer in number
Nucleus present
4000 – per mm3
Two types – Phagocytes and Lymphocytes

18. Platelets/Thrombocytes

19. What do platelets do? if you get cut:- platelets produce
tiny fibrin threads these form a web-like mesh that traps blood cells.
These harden forming a clot, or "scab."
This is useful for stopping bleeding, and for preventing germs from entering the body through the cut.
150,000 to 400,000 per mm3