1. Human Anatomy and Physiology II
Biology 1414
Unit 4
Respiratory Physiology

2. List and give the percentage of the main gases of the atmosphere.
Objective 1
List and give the percentage of the main gases of the atmosphere.
Unit 1 - Objective 1

3. Main Gases of the Atmosphere
Gas Symbol Approximate %
Nitrogen N
Oxygen O
Carbon Dioxide CO
Water Vapor H2O
Unit 1 - Objective 1

4. Objective 2
Define partial pressure and be able to compute partial pressures of gases in a mixture.
Unit 1 - Objective 2

5. Definition of Partial Pressure
Partial pressure refers to the pressure that is exerted by a single gas in some given system (atmosphere, blood, tissue, lung or experimental mixture). The sum of the individual partial pressures produces the total pressure in the system. This total pressure is called barometric pressure The barometric pressure of the atmosphere is 760 mmHg at sea level.
Unit 1 - Objective 2

6. Calculation of Partial Pressure
Partial pressure is directly proportional to the percentage of a gas in a mixture. In order to calculate the partial pressure of a gas, you will multiply the decimal equivalent of the percentage of a given gas by the total pressure of the system. The general formula would be:
partial pressure (P) = % of gas X total pressure
Unit 1 - Objective 2

7. Calculation of Partial Pressure Continued
If the percentage of oxygen in the atmosphere is 20.9% and the total barometric pressure of the atmosphere is 760 mmHg, then:
PO2 = X 760 mmHg.
This gives an oxygen partial pressure (PO2) of:
(159 rounded) mm Hg
Unit 1 - Objective 2

8. Calculation of Partial Pressure Continued
If the percentage of carbon dioxide in the atmosphere is 0.04% and the total barometric pressure of the atmosphere is 760 mmHg, then:
PCO2 = X 760 mmHg.
This gives a carbon dioxide partial pressure (PCO2) of:
0.304 (0.3 rounded) mm Hg
Unit 1 - Objective 2

9. Objective 3
Distinguish between pulmonary ventilation, external and internal respiration using short definitions.
Unit 1 - Objective3

10. Definition of Pulmonary Ventilation
Pulmonary ventilation is the exchange of air between the atmosphere and the lungs. This process is commonly called breathing and depends on chest and diaphragm movements, as well as, clear airways. Inhalation (inspiration) lowers pressure inside the lungs which draws in air. Exhalation does the opposite.
Unit 1 - Objective 3

11. Definition of External Respiration
External respiration is gas exchange between the lung alveoli and the blood of the pulmonary circulation. This process depends on gas partial pressure differences, the integrity of lung membranes and blood flow in and out of the lungs.
Unit 1 - Objective 3

12. Definition of Internal Respiration
Internal respiration is the exchange of gas between the blood and the cells of the body.
This process generally depends on the same factors as external respiration.
Unit 1 - Objective 3

13. Objective 4
Explain or interpret the movement of gases between alveolar spaces, blood and cells due to differences in partial pressure.
Unit 1 - Objective 4

14. Movement of Gases in the Body
Movement of gases between the alveoli, blood and cells depends on the partial pressure difference of a gas across these regions. According to the Law of Diffusion, gases always move from a region of high partial pressure to a region of low partial pressure. If your lungs have a higher gas pressure than your blood, then the gas will move into your blood and visa versa.
Unit 1 - Objective 4

15. Movement of Gases in the Body
Examine the following slide in order to observe the gas partial pressure differences that exist in different regions of the body. Predict the direction of oxygen and carbon dioxide movement from one region to another using the gas pressures.
Unit 1 - Objective 4

16. Movement of Gases in Body
Unit 1 - Objective 4

17. Name the ways carbon dioxide and oxygen are transported by the blood.
Objective 5
Name the ways carbon dioxide and oxygen are transported by the blood.
Unit 1 - Objective 5

18. Carbon Dioxide Transport
Method Percentage
Dissolved in Plasma %
Chemically Bound to
Hemoglobin in RBC’s %
As Bicarbonate Ion in
Plasma %
Unit 1 - Objective5

19. Oxygen Transport Method Percentage Dissolved in Plasma 1.5 %
Combined with Hemoglobin %
Unit 1 - Objective5

20. Objective 6
Write reactions to show the formation of each of the following in the blood. Be able to define and discuss the functional significance of each: oxyhemoglobin, carbaminohemoglobin, bicarbonate ion, carbonic acid.
Unit 1 - Objective 6

21. Oxyhemoglobin Formation
Oxyhemoglobin forms when an oxygen molecule reversibly attaches to the heme portion of hemoglobin. The heme unit contains iron ( +2 ) which provides the attractive force. The process is summarized as follows:
O2 + Hb
HbO2
Unit 1 - Objective 6

22. Carbaminohemoglobin Formation
Carbaminohemoglobin forms when a carbon dioxide molecule reversibly attaches to an amino portion of hemoglobin. The process is summarized as follows:
CO2 + Hb
HbCO2
Unit 1 - Objective 6

23. Carbonic Acid Formation
Carbonic acid forms abundantly in the RBC when the enzyme carbonic anhydrase stimulates water to combine quickly with carbon dioxide. The process is summarized as follows:
CO2 + H2 0
H2 CO3
Unit 1 - Objective 6

24. Bicarbonate Ion Formation
The bicarbonate ion also forms abundantly in the RBC when carbonic acid breaks down to release a hydrogen ion and bicarbonate. The process is summarized as follows:
H2 CO3
H HCO3
Unit 1 - Objective 6

25. Objective 7
Explain what takes place during the chloride shift and be able to diagram the chloride shift for tissue capillaries and pulmonary capillaries.
Unit 1 - Objective 7

26. Chloride Shift in Tissue Capillaries
When RBC’s move through tissue capillaries, they take in carbon dioxide and release bicarbonate. As bicarbonate is released, chloride (-1) shifts into the RBC in order to replace the negative bicarbonate (-1). This preserves charge balance in the RBC. To see this, look at the next slide.
Unit 1 - Objective 7

27. Chloride Shift in Tissue Capillaries
Tissue Capillary
Unit 1 - Objective 4

28. Chloride Shift in Pulmonary Capillaries
When RBC’s move through pulmonary capillaries, they take in bicarbonate and release carbon dioxide. As bicarbonate (-1) shifts into the RBC, chloride (-1) shifts out of the RBC. This also preserves charge balance in the RBC. To see this, look at the next slide.
Unit 1 - Objective 7

29. Chloride Shift in Pulmonary Capillaries
Pulmonary Capillary
Unit 1 - Objective5

30. Objective 8
Given an oxygen dissociation curve, determine the percent of hemoglobin saturation with oxygen for a given PO2 and PCO2. Discuss the influence of the Bohr effect on hemoglobin saturation.
Unit 1 - Objective 8

31. The Oxygen Dissociation Curve
Examine the following oxygen dissociation curve and give the percent saturation at the following partial pressures of oxygen:
PO Percent Saturation
100 mm Hg ?
40 mm Hg ?
26 mm Hg ?
Unit 1 - Objective 8

32. The Oxygen Dissociation Curve
Unit 1 - Objective 8

33. The Oxygen Dissociation Curve
The answers for the previous activity are as follows:
PO Percent Saturation
100 mm Hg
40 mm Hg
26 mm Hg
Unit 1 - Objective 8

34. The Bohr Effect
When the carbon dioxide content of the blood increases, the oxygen dissociation curve shifts to the right. This right shift decreases the ability of hemoglobin to hold oxygen. Consequently, additional oxygen is unloaded and made available to the body. See the following graph for this effect.
Unit 1 - Objective 8

35. Bohr Effect
Bohr Shift Curve
Unit 1 - Objective 8

36. The Bohr Effect
Did you notice that when PCO2 increased from 40 to 80 mm Hg, oxygen saturation decreased from 75 % to about 65 %. This made an extra 10% oxygen available to the tissues. This would come in handy during increased activity. The Bohr shift is a very positive adaptation!
Unit 1 - Objective 8

37. Objective 9
Cite or recognize four reasons why oxyhemoglobin is induced to give off oxygen in tissue capillaries
Unit 1 - Objective 9

38. Factors That Induce Oxygen Unloading From Hemoglobin
In addition to carbon dioxide that causes a right shift in the oxygen dissociation and more oxygen unloading, there are additional factors that cause a similar effect:
1. Increased body temperature
2. Increased H+ from acids
3. Increased 2,3-biphosphoglygerate
(BPG)
Unit 1 - Objective 9

39. Objective 10
Give the location and function of the respiratory centers and list five factors that influence the centers.
Unit 1 - Objective 10

40. Location of Respiratory Centers
The pons contains the pneumotaxic respiratory center and the apneustic respiratory center. Both of these centers are considered secondary respiratory centers. This means they do not set the basic respiratory rhythm. Instead, they modify the basic respiratory rate. The medulla contains the medullary respiratory center that operates as the primary breathing center.
Unit 1 - Objective 10

41. Location of Respiratory Centers
View the following diagram for the location of the respiratory centers
Unit 1 - Objective 10

42. Respiratory Centers
Medullary Respiratory Center
Unit 1 - Objective

43. Function of Respiratory Centers
The pneumotaxic respiratory center inhibits inhibits inspiratory time and increases breaths per minute. The apneustic respiratory center has not been clearly defined, but, is postulated to prolong inspiratory time and reduces breaths per minute. The medullary respiratory center stimulates basic inspiration for about 3 seconds and then basic expiration for about 2 seconds (5sec/breath= 12breaths/min).
Unit 1 - Objective 10

44. Factors That Influence Respiration
View the following slide for factors that influence respiration
Unit 1 - Objective 10

45. Factors Influencing Respiration
Unit 1 - Objective