Transport in Human ( 人類的運輸系統 )

1. Transport in Human(人類的運輸系統)

2. Every cell requires food, oxygen & other useful materials for metabolism(代謝作用). Food Metabolism Oxygen Useful materials

3. Metabolism produces toxic waste products which must be removed. Metabolism Toxic waste products e.g. carbon dioxide

4. Many cells are far away from the small intestine and the lung. A transport system is developed to increase the efficiency of exchange and transport of materials. O2 CO2 Food

5. Transport System Blood 血液 Blood vessels 血管 Heart 心臟

6. Blood Cells Blood Platelet White Blood Cell Red Blood Cell

7. Blood • Plasma (血漿) (55%) • 90% water • Dissolved substances: • Dissolved food substances • Plasma Proteins • Wastes • Blood cells (血細胞) (45%) • Red blood cells • White blood cells • Blood platelets

8. Red Blood Cells • carry oxygen from lungs to all parts of body

9. White Blood Cells • kill germs (病菌) • help to defend (防衛) us against diseases

10. Blood Platelets • are involved in blood clotting (凝血作用)

11. Blood cells are produced bybone marrow(骨髓).

12. Heart Vein (靜脈) Artery (動脈) Capillaries (微血管) Blood Vessels

13. Arteries • carry blood fromheart to other parts of the body • thick wall with muscles • branch into capillaries

14. Capillaries • the smallest blood vessels • reach every part of the body

15. Capillaries • have very thin walls => substances can diffuse across their walls • are the places for exchange of materials between the blood and the cells CO2, wastes O2 glucose Tissue cell

16. Veins • Capillaries join up to form veins. • carry blood back to heart • thinner walls with less muscles • have valves(瓣膜) to prevent backflow of blood (血液倒流)

17. Valves closed Valves open Valves open Valves closed Backflow of blood is prevented by valve. How do valves preventbackflow of blood? Muscle contracts Blood is propelled forward Muscle relaxes

18. Which one is artery?Which one is vein? Why? Because the wall of artery is thicker than that of vein.

19. Heart

20. Structure of a Heart Pulmonary artery (肺動脈) Aorta (大動脈) Right auricle (右心耳) Left auricle (左心耳) Left ventricle (左心室) Right ventricle (右心室) - supply blood to the heart Coronary blood vessels (冠狀血管)

21. Heart structure Auricles - receive blood from body Left Right Pulmonary veins Veins From other parts of body From lungs

22. Heart structure Ventricles - pump blood out of the heart Right Left Pulmonary Artery Aorta To other parts of body To lungs

23. Structure of a human heart Aorta Pulmonary artery Pulmonary veins Vein Left auricle Right auricle Valves Vein Left ventricle Right ventricle

24. Blood Circulation (血液循環) Blood flow is maintained by pumping action of the Heart.

25. O2 CO2 Pulmonary Circulation (肺循環) • Deoxygenated blood (缺氧血) returns from body to the right auricle. • Right auricle contracts and pump blood to the right ventricle. • Right ventricle pumps blood to lungs through pulmonary artery. • Gaseous exchange (氣體交換) in lungs; blood becomes oxygenated blood(含氧血) • Oxygenated blood flow back to left auricle and then to left ventricle through pulmonary vein. Oxygenated Blood (含氧血) Deoxygenated Blood (缺氧血) body

26. Systemic Circulation (體循環) • Left ventricle pumps oxygenated blood to all parts of body (except lungs) via aorta. • After flowing through body, the blood becomes deoxygenated. • The blood flows back to the heart. Oxygenated Blood (含氧血) body body Deoxygenated Blood (缺氧血)

27. Double Circulation (雙循環) • Blood flows through the heart twice in one complete circulation • Consists of 2 circuits: • Connection between heart with lungs . • Connection between heart with the rest of the body .

28. Is it possible that blood flows backwards in heart? Why?

29. Backflow of blood in heart is prevented by valves .

30. Valves (瓣膜)

31. Useful Websites • http://www.ehc.com/vbody.asp • http://www.mercksharpdohme.com/disease/heart/coronary_health/anatomy/home.html

32. Eating for healthy transport system • Takes in too much fat in diet will make us put on weight easily • Fatty foods also contain a lot ofcholesterol • Cholesterol is a fatty substance found in the blood. It is used to makecell membranesand some hormones.

33. Eating for healthy transport system • Do you remember the chart used in teaching Diet and Health? • we can also obtain nutritive values of common food from the website of Centre for Food Safety (食物安全中心)：http://www.fehd.gov.hk/niis/presearch3.html

34. Too much cholesterol can deposit on the inner walls of blood vessels and harden the walls.

35. The vessels cannot expand easily when blood is forced into them. This will result in high blood pressure.

36. Eating for healthy transport system • Cholesterol deposits may block the coronary arteries that supply oxygen&nutrients to the heart muscle and coronary heart disease results. • The heart may stop beating due to the lack of oxygen and this may cause death.

37. Eating for healthy transport system • If there is a blockage or rupture in the brain arteries, stroke may result. This may result in paralysis. • To avoid the trap of cholesterol in the body, it is recommended that we limit our average daily cholesterol intake to less than 300 mg.