1. The Respiratory System

2. ANATOMY OF THE RESPIRATORY SYSTEM

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

4. 1) Respiratory Tract: 2) The lungs.
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

10. Bronchioles and Alveoli

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

12. Ciliary Lining of the Lower Respiratory Tract
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. Alveoli consists 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
3) The Abdominal Muscles
4) Internal Intercostal Muscles
- Extra Expiration muscles
1) The Diaphragm
2) External Intercostal Muscles
- Inspiration muscles
- increases the anteroposterior and transverse dimensions of the chest.
- the principal muscle of inspiration
- pulls the diaphragm down, increasing all three dimensions of the thoracic cage.

42. Lungs and Thoracic Cage
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. 2) external intercostal muscles
Inspiration
Contraction of
1) diaphragm
2) external intercostal muscles 
The lungs are carried along.
 Lung volume
 pressure
Air flows in.
active

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

49. 1) diaphragm 2) external intercostal muscles
Forced Expiration
Relaxation of
1) diaphragm 2) 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

51. Resistance to Airflow

52. TABLE OF CONTENTS Resistance 1) Alveolar Surface Tension
2) Elastic Resistance
Airway Resistance
Compliance

53. Alveolar Surface Tension
- generated by a thin film of liquid over the surface of alveolar epithelium,
- tends to cause a collapse of the alveoli,
- Resists against inspiration.

54. Alveolar surface tension is a resistance against inspiration.
Alveoli

55. Surface tension is reduced by surfactant.
( type II alveolar epithelial cells)
Pre-term infants don't have enough surfactant.
type II
surfactant

56. Resistance 1) Alveolar Surface Tension 2) Elastic Resistance
Airway Resistance
- Against inspiration due to elastic fibers in the lungs and chest wall,
- Increases in pulmonary fibrosis.

57. Resistance 1) Alveolar Surface Tension 2) Elastic Resistance
Airway Resistance
- Due to friction, affected by airway caliber.
- Against inspiration and expiration!
- Increases during asthma attack (smooth muscle contraction in bronchiole.

58. Resistance Compliance 1) Alveolar Surface Tension
2) Elastic Resistance
Airway Resistance
Compliance
- The reciprocal of resistance,
- An indicator of ease with which the lungs expand.

59. Measurements of Ventilation using Spirometer

61. Dead Space Alveolar ventilation rate =
(tidal volume – dead space) x resp freq (/min)
inspiration
expiration
Dead Space

62. Changes in Spirometric Measures
Restrictive disorders
- (pulmonary fibrosis)
- compliance & vital capacity.

63. Changes in Spirometric Measures
Obstructive disorders
- No change in respiratory volumes
-  FEV1.
one-second forced expiratory volume

64. SUMMARY MECHANICS OF VENTILATION Driving Force for Air Flow
Resistance to Airflow
Measurements of Ventilation
Alveolar Ventilation

65. NEURAL CONTROL OF VENTILATION

66. Rhythm?

67. Center in the medulla oblongata
1) inspiratory center
- stimulates inspiration muscles.
2) expiratory center
inhibits the inspiratory center,
stimulates expiration muscles.

68. The pons fine-tunes ventilation.

69. Afferent Connections to the Respiratory Centers
the limbic system
Hypothalamus
Chemoreceptors
the lungs

70. Chemoreceptor-initiated Reflexes
Peripheral chemoreceptors
- aortic and carotid bodies,
- monitor O2, CO2 and pH of the blood.
Central chemoreceptors
- close to the surface of the medulla oblongata,
- monitor the pH of the cerebrospinal fluid.

71. stimulate chemoreceptors frequency and depth of respiration
CHEMORECEPTOR-MEDIATED REFLEX
O2, CO2, or pH
stimulate chemoreceptors
reflex
frequency and depth of respiration

72. Voluntary Control - the motor cortex,
- bypass the brainstem respiratory centers,
- limited voluntary control.

73. GAS EXCHANGE in the LUNGS

74. ventilation
gas exchange
transport by blood
gas exchange

75. - Diffusion of a gas is driven by O2 and CO2 partial pressure gradient.
PO2 = 40 mmHg
PCO2 = 46 mmHg
PO2 = 104 mmHg
PCO2 = 40 mmHg
- The gas exchange between alveolar air and the blood is via diffusion of O2 and CO2.

76. The partial pressure of a gas refers to the share of the total pressure generated by a mixture of gases.
104 mmHg O2
CO2 N2
H2O
13.6%
40 mmHg
5.3%
Total = 760 mmHg

77. Oxygen and carbon dioxide cross the respiratory membrane and the air-water interface easily.
PO2 = 40 mmHg
PCO2 = 46 mmHg
PO2 = 104 mmHg
PCO2 = 40 mmHg

78. Overview of Gas Exchange in the Lungs

79. Factors That Affect the Efficiency of Alveolar Gas Exchange
1. partial pressure
solubility
respiratory membrane thickness/area
ventilation-perfusion coupling

80. Air 1) Partial pressure a) High altitude b) Hyperbaric chamber
PO2104 mmHg
PCO2 40 mmHg
a) High altitude
b) Hyperbaric chamber
c) Obstructive disease O2
CO2 N2
H2O O2
CO2
Air N2
Total = 760 mmHg
Total = 760 mmHg

81. CO2 has a higher solubility than O2. CO2 O2
1) Partial pressure
PO2 40 mmHg
PCO2 46 mmHg
2) Solubility
PO2104 mmHg
PCO2 40 mmHg
CO2 has a higher solubility than O2.
CO2 O2
Pressure Gradient 6 mmHg 64 mmHg

82. 1) Partial pressure
2) Solubility
3) Respiratory membrane thickness/area

83. 3) Respiratory membrane thickness/area
1) Partial pressure
2) Solubility
3) Respiratory membrane thickness/area
4) Ventilation-perfusion Coupling
- average V-P ratio = 0.8
- autoregulated by:
PO2 and PCO2
causes:
vasoconstriction of pulmonary arterioles
dilation of bronchioles

84. summary 1) Driving force for gas exchange
2) Factors that affect the efficiency of alveolar gas exchange

85. Gas transport by the blood

86. TABLE OF CONTENT
1) Carbon Dioxide Transport
2) Oxygen Transport

87. Carbon Dioxide Transport
7% dissolved in the blood as a gas,
23% as carbamino-hemoglobin,
70% as carbonic acid in the plasma.

88. Oxygen Transport
- About 98.5% of O2 in the blood are carried by hemoglobin.
- The rest is physically dissolved in plasma.

89. saturation of hemoglobin
Hypoxemia
Blood Oxygen Content
average 20 ml/dL
determined by:
saturation of hemoglobin
2) content of hemoglobin
Hypoventilation
CO poisoning
anemia

91. How to dissociate? O2 GAS EXCHANGE in the TISSUES
1. Carbon Dioxide Loading
2. Oxygen Unloading

92. O2 Dissociation of O2 from hemoglobin (HB) is affected by:
PO2  dissociation
PCO2  dissociation
pH  dissociation
DPG  dissociation
(2,3-diphosphoglycerate)
Temperature  dissociation O2

93. O2 100% saturated In Lungs High PO2, low PCO2  association with HG
favor the loading of O2 O2
100% saturated

94. O2 In tissues High PCO2, low PO2, low pH, DPG
 dissociation of O2 from HG
favor the unloading O2

95. O2 In tissues High PCO2, low PO2, low pH, DPG
 dissociation of O2 from HG
favor the unloading O2

96. Utilization Coefficient
- The amount of oxygen uptake by tissue versus the arterial blood oxygen content
20 ml O2/dL
15.6 ml O2/dL
blood
4.4 ml O2/dL
cell
cell
cell
cell
cell
Utilization Coefficient = 4.4 ml / 20 ml = 22%

97. Function of Oxygen ?

98. glucose
without oxygen
with oxygen
2 ATP
38 ATP

99. Can human beings produce oxygen?

100. Oxygen Toxicity
- Excessive oxygen generates hydrogen peroxide and free radicals, which destroy enzymes and damage nervous tissue.
Oxidative toxicity with aging.

101. Hypercapnia Hypocapnia PCO2 > 43 mmHg
caused by hypoventilation (respiratory diseases)
Hypocapnia
PCO2 < 37 mmHg
caused by hyperventilation

102. of the Respiratory System
Summary
of the Respiratory System

103. ventilation
gas exchange
transport by blood
gas exchange

104. Oxyhemoglobin Dissociation Curve

105. Oxygen Dissociation & Temperature
Active tissue - more O2 released
PO2 (mmHg)

106. Oxygen Dissociation & pH
Active tissue - more O2 released
Bohr effect: release of O2 in response to low pH