Think about… 7.1 The human breathing system 7.2 Gas exchange in the air sacs

2. Think about… 7.1 The human breathing system 7.2 Gas exchange in the air sacs 7.3 Transport of respiratory gases 7.4 Ventilation Recall ‘Think about…’ Summary concept map

3. building up of CO ? 2 What makes us yawn? tired? bored?

4. What makes us yawn? The answer is…

5. What makes us yawn? …still a mystery.

6. Which parts of our body are in action when we yawn 1

7. Where does the exchange of oxygen and carbon dioxide take place between our body and the atmosphere 2

8. In what forms are oxygen and carbon dioxide carried around our body 3

9. 7.1 The human breathing system gas exchange(氣體交換) O2 CO2

10. 7.1 The human breathing system In very small organisms: O2 CO2 • diffuses across cell membrane

11. 7.1 The human breathing system In larger organisms:  O2  CO2 • cannot diffuse across body surface

12. 7.1 The human breathing system In larger organisms: • breathing system (呼吸系統) - for gas exchange • transport system (運送系統) - for carrying gases to body cells

13. 7.1 The human breathing system What does the human breathing system consist of?

14. 7.1 The human breathing system Human breathing system nasal cavity 3D Model nostril pharynx epiglottis larynx trachea bronchiole bronchus air sac lung

15. 7.1 The human breathing system Human breathing system rib diaphragm

16. 7.1 The human breathing system Human breathing system intercostal muscle outer pleural membrane pleural cavity inner pleural membrane

17. 7.1 The human breathing system How does air flow into the lungs? air

18. 7.1 The human breathing system air nasal cavity pharynx larynx trachea

19. 7.1 The human breathing system air bronchus bronchiole air sac

20. 7.1 The human breathing system 7.1 Examination of the mammalian breathing system 1 Examine the breathing system of a dissected rat or a human torso model. 2 Identify the various structures.

21. 7.1 The human breathing system 1 Nostrils and nasal cavity i) Hairs • filter larger dust particles

22. 7.1 The human breathing system 1 Nostrils and nasal cavity ii) Mucus-secreting cells traps dust particles & moistens air mucus

23. 7.1 The human breathing system 1 Nostrils and nasal cavity iii) Ciliated epithelial cells sweep mucus with dust particles towards pharynx cilia

24. 7.1 The human breathing system 1 Nostrils and nasal cavity iv) Capillaries • blood warms up air

25. 7.1 The human breathing system 2 Pharynx and larynx pharynx larynx oesophagus trachea

26. 7.1 The human breathing system 2 Pharynx and larynx food larynx oesophagus

27. 7.1 The human breathing system 2 Pharynx and larynx 1 Tongue pushes food towards pharynx larynx oesophagus

28. 7.1 The human breathing system 2 Pharynx and larynx 2 Soft palate moves up, preventing food from entering nasal cavity larynx oesophagus

29. 7.1 The human breathing system 2 Pharynx and larynx 3 Larynx rises and epiglottis covers entrance to trachea, preventing choking larynx oesophagus

30. 7.1 The human breathing system 2 Pharynx and larynx

31. 7.1 The human breathing system 2 Pharynx and larynx epiglottis larynx • made up of cartilage

32. 7.1 The human breathing system 2 Pharynx and larynx vocal cords (聲帶) • can vibrate to produce sound

33. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles trachea bronchus bronchioles

34. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles trachea bronchus bronchioles

35. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles lumen C-shaped cartilage • prevents collapse ciliated epithelial cell

36. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles Ciliated epithelial cells

37. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles Mucus-secreting cells Absent in smaller bronchioles

38. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles Capillaries

39. 7.1 The human breathing system 3 Trachea, bronchi and bronchioles Cartilage C-shaped Circular Absent

40. 7.1 The human breathing system air sac 4 Air sacs • large respiratory surface capillary

41. 7.1 The human breathing system 5 Lungs • composed of bronchioles and air sacs • in thoracic cavity (胸腔)

42. 7.1 The human breathing system 5 Lungs • protected by rib cage (肋骨籃) vertebral column (脊柱) ribs sternum (胸骨) cartilage

43. 7.1 The human breathing system 5 Lungs intercostal muscles diaphragm • sheet of muscle

44. 7.1 The human breathing system 5 Lungs

45. 7.1 The human breathing system 5 Lungs rib intercostal muscle outer pleural membrane right lung inner pleural membrane pleural cavity

46. 7.1 The human breathing system 5 Lungs • pleural cavity filled with pleural fluid (胸腺液) as lubricant (潤滑劑) right lung pleural cavity

47. 7.1 The human breathing system 7.2 Examination of the pig lungs 1 Examine the pig lungs. Identify the larynx, epiglottis, trachea, bronchi, left and right lungs.

48. 7.1 The human breathing system 7.2 2 The lungs have several lobes. Find out the number of lobes present in the left and the right lungs respectively.

49. 7.1 The human breathing system 7.2 3 Feel the hardness of the trachea and the lung tissue with a pair of forceps. 4 Use a water hose to fill the lungs with water through the trachea. Note the changes in the volume of the lungs. 5 Draw a labelled diagram of the lungs.

50. 7.1 The human breathing system 1a The human breathing system consists of the and structures that aid breathing. respiratory tract