1. The Respiratory System
Chapter 23
(6th edition chapter 22)

2. Functions of the Respiratory System
Supply oxygen to the circulatory system for delivery to the tissues
Remove CO2 (and some other wastes) from blood.

3. There are 4 processes that we call “respiration”.
Pulmonary ventilation - Movement of air into and out of the lungs
(also referred to as “breathing”).
2. External respiration - Gas exchange in the lungs between the blood
of the capillaries and the spaces in the air sacs (alveoli)
Transport - The movement of gases by the circulatory system
Strictly speaking, a function of the blood.
Internal respiration - Gas exchange between the blood and the
tissues of the body

4. Overview of respiratory system anatomy

5. External Structures of the nose

6. Nasal skeletal structures

7. Internal anatomy of the upper respiratory tract

8. The larynx and associated structures

9. Cross section of the trachea and esophagus

10. The Lungs

11. The Lungs

12. The lower lung

13. Alveoli and the respiratory membrane

14. Structure of an alveolar sac

15. Respiratory Physiology
Boyle’s law: P1V1 = P2V2

16. Pressure relationships The negative intrapleural pressure keeps the lungs inflated

17. Mechanics of Breathing: Inspiration

18. Mechanics of Breathing: Expiration

19. Changes in pressure & volume relationships

20. Respiratory Physiology
Resistance:
F = P/R
R = resistance
P = change in pressure (the pressure gradient)

21. Respiratory Volumes

22. Respiratory Physiology: Dalton’s Law of Partial Pressures
The total pressure of a mixture of gases is the sum of the partial
pressures exerted independently by each gas in the mixture.
Location
Atmosphere at sea level
Alveoli of lungs
Gas
Approximate %
Partial pressure in mmHg N2
78.6
597
74.9
569 O2
20.9
159
13.7
104
CO2
0.04
0.3
5.2 40
H2O
0.46
3.7
6.2 47
Total
100.0
760

23. Partial pressure relationships: Movement of gases between the lungs and the tissues

24. Most soluble Least soluble
Solubility: Differential solubility of gases contributes to the balance of gas exchange
Most soluble Least soluble
CO2 >>>>>>>>>>>>>>>>> O2 >>>>>>>>>>>>>>>>>>> N2
CO2 is 20 times more soluble than O2
N2 is about half as soluble as O2

25. Ventilation-Perfusion Coupling Breathing and blood flow are matched to the partial pressure of alveolar gases

26. Respiratory Gas Transport
Oxygen - about 98.5% is bound to hemoglobin (Hb) and 1.5% in solution.
The affinity of O2 for hemoglobin is influenced by partial pressure

27. Factors influencing Hb saturation: Temperature

28. Factors influencing Hb saturation: Pco2 and pH

29. BPG (2,3-bisphosphoglycerate)
The Bohr Effect
Decreased pH that results from increased Pco2 lowers the binding
affinity between O2 and Hb. The result is that, under acidosis, Hb
saturates at a lower Po2. This allows more oxygen to be unloaded at the
where it is needed.
BPG (2,3-bisphosphoglycerate)
This compound is produced during glycolysis, anaerobic means of
producing energy from glucose. BPG binds to Hb and decreases O2
affinity. This results in a right-shifted O2 - Hb dissociation curve,
Like we see in the Bohr effect

30. CO2 Transport 7 - 10% dissolved in the plasma
~ 20% bound to the amine groups of the Hb molecule as
carbaminohemoglobin
~ 70% as bicarbonate ion in the plasma

31. CO2 Transport & Exchange: at the tissues

32. CO2 Transport & Exchange: in the lungs

33. The Haldane Effect

34. Control of Respiratory Rhythm

35. Medullary Respiratory centers
Neural and chemical
influences

36. Pco2 & pH are the primary regulators of ventilation by means of negative feedback

37. Pathology and clinical considerations
Common homeostatic imbalances:
COPD (chronic obstructive pulmonary disease)
Asthma
Tuberculosis
Lung cancer

38. COPD: Emphysema
Results: Loss of lung elasticity, hypoxia, lung fibrosis, cyanosis.
Common causes: Industrial exposure, cigarette smoking.

39. Tuberculosis At the beginning of the 20th century a third of
all deaths in people
were from TB.
Antibiotic-resistant strains
of Mycobaterium tuberculosis
are a growing problem at the
beginning of the 21st century.

40. Lung Cancer

41. 90% of lung cancer patients had one thing in common…

42. …they smoked tobacco

43. Fin