Why do organisms need a transport system?

1. Why do organisms need a transport system? • In large organisms, the distance over which oxygen, carbon dioxide, nutrients and wastes have to move is too L-O-N-G for food absorption and gaseous exchange to occur efficiently

2. Transport Systems in Humans Circulatory System Lymphatic System

3. Circulatory System

4. BLOOD Human Circulatory System BLOOD VESSELS HEART

5. Blood is a LIQUID TISSUE consisting of blood cells which float in a liquid Blood acts as a TRANSPORT MEDIUM to carry various substances in the forms of solution and suspension Blood

6. Blood • The various components in blood can be separated by a machine called a CENTRIFUGE • After centrifugation, blood is divided into two portions

7. Blood Plasma (55% by volume) (straw colour) Blood Cells (45% by volume) (red colour)

8. What is blood made up of?

9. BLOOD CELLS 250 000/mm3 7 000/mm3 5 000 000/mm3

10. Blood Cells White Blood Cell Red Blood Cell Platelet

11. Where are blood cells made?

12. Red Blood Cells (Erythrocytes )

13. Red Blood Cells • RBC’s are formed in BONE MARROW • They have a short life-span: about 120 days only • Old RBC’s are destroyed in the liver and the spleen • Matured RBC’s in mammals do not possess a nucleus

14. Red Blood Cells • They are shaped like biconcave discs in order to provide a large surface area for diffusion of gases • Their red colour comes from haemoglobin which is responsible for carrying oxygen from the lungs to all parts of the body

15. Transport of Oxygen

16. Transport of Oxygen

17. Transport of Oxygen

18. In Lungs Haemoglobin (Purplish Red) Oxyhaemoglobin (Bright Red) + Oxygen In Tissues Transport of Oxygen

19. Transport of Carbon Dioxide • Most of the carbon dioxide is carried in the blood in the form of hydrogencarbonate ions (HCO3-). An enzyme inside the RBC helps to convert the CO2 into HCO3- and vice versa

20. Investigation #1: To investigate the effects of oxygen and carbon dioxide on chicken’s blood

21. Procedure

22. Irregularly-shaped Possess nucleus Kill pathogens Number of WBC’s in body can vary Different WBC’s have different lifespans: ranging from 10 hours to over 1 year White Blood Cells (Leukocytes)

23. White Blood Cells 1) Phagocytes • They are made in the bone marrow • They have a lobed nucleus • They can move like an Amoeba out of blood capillaries to engulf germs and dead cells

24. Phagocytes

25. Bacteria Phagocyte

26. White Blood Cells 2) Lymphocytes • They have a large nucleus • They are made in the bone marrow and then migrate to lymph nodes • Some lymphocytes produce antibodies; others kill invading cells directly • They also produce antitoxins to neutralize toxins produced by germs

27. When the lymphocyte encounters a matching antigen, the antibody interlocks with the antigen and marks it for destruction

30. Leukaemia • Leukaemia is a cancer of the tissues which produce blood • Large numbers of abnormal white cells are produced, which are unable to carry out their normal function of fighting infection • The abnormal cells also displace the normal production of red cells and platelets • Can be treated with chemotherapy, radiotherapy or bone marrow transplant

31. Platelets (Thrombocytes) • Tiny fragments formed from specialized cells in the bone marrow • They have no nucleus • They have a short life span: less than 10 days • They are involved in the process of blood clotting

32. Platelets

33. After the clot is formed, bleeding is stopped. The clot hardens to form a scab and the wound gradually heals

34. Blood Clotting Blood vessel constricts to slow down blood loss RBC’s trapped in a network of fibrin threads Platelet plug

35. Blood Clotting

37. A Comparison of RBC’s, WBC’s and Platelets Red blood cells White blood cells Platelets Bone marrow, lymph nodes Bone marrow Bone marrow Site of production Number 5 000 000/mm3 7 000/mm3 250,000/mm3 Lym:8-10m Phag:12m Tiny cell fragments Size 8m diameter Biconcave disc-shaped Shape Irregular Irregular No nucleus Haemogloblin Nucleus No haemoglobin No nucleus No haemoglobin Structure Function Blood clotting Transport of oxygen Body defence

38. PLASMA Dissolved Substances (10%) Water (90%)

39. Plasma – Dissolved Substances • Plasma proteins – antibodies, fibrinogen • Lipids • Glucose • Amino acids • Hormones – coordinate body activities • Mineral salts • Urea • Carbon dioxide Nutrients Wastes

40. Investigation #2: Detecting the presence of glucose in a blood sample

41. Procedure

42. Functions of Blood Transportation of: 1. Oxygen – in the form of oxyhaemoglobin 2. Carbon dioxide – in the form of HCO3- 3. Food – from ileum to all parts of body 4. Urea – from liver to kidneys 5. Hormones – from endocrine glands 6. Antibodies – to all parts of body 7. Heat – to keep uniform temperature

43. Functions of Blood Defence against infection: 1. Phagocytes engulf germs 2. Lymphocytes produce antibodies to destroy germs or antitoxins to neutralize toxins 3. Blood clotting prevents excess blood loss and entrance of bacteria

45. Blood Vessels A system of tubes for distributing blood around the body: • Artery – carry blood AWAY from the heart • Vein – carry blood TOWARDS the heart • Capillary – narrow vessel connecting arteries and veins * Arteries branch into smaller vessels called arterioles * Small vessels called venules join into veins

48. Changes in blood pressure in different types of blood vessels 16 Blood pressure (kPa) 8 With pulse No pulse Capillaries Veins Arteries Arterioles Venules

50. Carry blood AWAY from the heart Contain oxygenated blood (exception: pulmonary artery) Thick walls of muscles Elastic fibres allow arterial wall to withstand pressure Lumen is small and appeared to be round No valves Need to withstand high pressure The muscles around the artery can contract or relax to allow the vessel to constrict or dilate Arteries