The Respiratory System

1. The Respiratory System

2. ANATOMY OF THE RESPIRATORY SYSTEM

3. TABLE OF CONTENT The Respiratory Tract: The Lungs Alveoli

4. THE RESPIRATORY SYSTEM CONSISTS OF: 1) Respiratory Tract: Nose through bronchi 2) The lungs.

5. The respiratory tract further divided into the upper and lower respiratory tract

6. The upper respiratory tract from the nose through the pharynx

7. The lower respiratory tract (The Bronchial Tree) from the larynx to tertiary bronchi

8. The Bronchial Tree

9. The Bronchial Tree Extends to Bronchioles and Alveoli Alveoli

10. Bronchioles and Alveoli

11. Cartilage Ring asthma attack Cartilage Plates Bronchioles No Cartilage but Smooth Muscles

12. Ciliary Lining of the Lower Respiratory Tract Cilia Longitudinal Section Cross Section

13. Electron Micrograph of Cilia

14. The cilia beat upward and drive the debris-laden mucus to the pharynx, where it is swallowed.

15. THE LUNGS

16. The Lungs overlap with the respiratory tract. Inside Lungs Primary Bronchi Secondary Bronchi Bronchioles Alveoli Tertiary Bronchi

17. THE LUNGS - consist of the left and the right lungs - The left lung is divided into two lobes; the right into three. • receives the bronchus, blood and lymphatic vessels, and nerves through its hilum. • - The bronchi extend into alveoli

18. ALVEOLI

19. ~700 SF surface area

20. Alveoliconsists of : 1) type I alveolar cells (95%), thin 2) type II alveolar cells (5%), secrete surfactant. 3) macrophages (dust cells), defense

21. - Each alveolus is surrounded with a basket of capillaries.

22. surrounded with capillaries

23. The respiratory membrane: 1) the wall of the alveolus 2) the endothelial wall of the capillary 3) their fused basement membranes

24. Alveoli contain elastic fibers which helps expiration.

25. Low blood pressure keeps alveoli dry.

26. Gas exchange occurs only in alveoli.

27. Dead Space • - starts from nose to terminal bronchiole • where there is no gas exchange • ~ 150 ml terminal bronchiole

28. SUMMARY ANATOMY OF THE RESPIRATORY SYSTEM The Respiratory Tract: The Lungs Alveoli

29. ventilation gas exchange transport by blood gas exchange

30. MECHANICS OF VENTILATION

31. TABLE OF CONTENTS Driving Force for Air Flow Resistance to Airflow Measurements of Ventilation Alveolar Ventilation

32. Terms: inspiration or inhalation: breathing in expiration or exhalation: breathing out

33. Driving Force for Air Flow Airflow driven by the pressure difference between atmosphere (barometric pressure) and inside the lungs (intrapulmonary pressure). 760 mmHg

34. atmospheric pressure = 760 mmHg Before inspiration

35. atmospheric pressure = 760 mmHg

36. atmospheric pressure = 760 mmHg

37. atmospheric pressure = 760 mmHg

38. Mechanism for the Change in Intrapulmonary pressure Boyle’s Law: Volume x Pressure = Constant P V gas

39. Inspiration: Expiration:  Volume   Pressure  Volume   Pressure

40. Inspiration: Expiration:  Volume   Pressure  Volume   Pressure Can the lungs expand/shrink by themselves?

41. Major Respiratory Muscles 1) The Diaphragm 2) External Intercostal Muscles 3) Internal Intercostal Muscles 4) The Abdominal Muscles 1) The Diaphragm 2) External Intercostal Muscles 3) The Abdominal Muscles - Expiration muscles - pulls the diaphragm up, reducing the vertical dimension of the thoracic cage. 1) The Diaphragm 2) External Intercostal Muscles - Inspiration muscles - increases the anteroposterior and transverse dimensions of the chest. 1) The Diaphragm 2) External Intercostal Muscles 3) The Abdominal Muscles 4) Internal Intercostal Muscles - Extra Expiration muscles - the principal muscle of inspiration - pulls the diaphragm down, increasing all three dimensions of the thoracic cage.

42. Coupling Between Lungs and Thoracic Cage

43. - The lungs and thoracic cage are coupled by the pleurae. Visceral pleura covers the surface of each lung; parietal pleura lines the chest cavity. - The two pleurae form the pleural cavity. - The pleural fluid serves to reduce friction during chest expansion. - Intrapleural pressure: The pressure in the pleural cavity is negative. pleural cavity

44. Parietal pleura visceral pleura lung Potential pleural cavity (negative intrapleural pressure) Generation of the negative intrapleural pressure The thoracic cage is larger than the natural size of the lungs.

45. Parietal pleura visceral pleura lung Potential pleural cavity (negative intrapleural pressure) pneumathorax air air

46. Conclusion pleurae Lungs Thoracic Cage - pressure

47. Inspiration • Contraction of • 1) diaphragm • 2) external intercostal muscles •  • The lungs are carried along. •  •  Lung volume •  •  pressure •  • Air flows in. active

48. Resting Expiration • Relaxation of • 1) diaphragm • 2) external intercostal muscles •  • The lungs shrink. •  •  Lung volume •  •  pressure •  • Air flows out. passive

49. Forced Expiration • Relaxation of • 1) diaphragm2) external intercostal muscles • and • Contraction of • abdominal, internal intercostal and other accessory respiratory muscles. •  •  Lung volume •  •  pressure •  • Air flows out. active

50. SUMMARY • Driving Force for Air Flow • Atmosphere-lung pressure gradient • Major respiratory muscles • Coupling between lungs and thoracic cage