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Human Anatomy and Physiology II

Human Anatomy and Physiology II. Biology 1414 Unit 4 Respiratory Physiology. Objective 1. List and give the percentage of the main gases of the atmosphere. Unit 1 - Objective 1. Main Gases of the Atmosphere. Gas Symbol Approximate % Nitrogen N2 78.6

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Human Anatomy and Physiology II

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

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

  3. Main Gases of the Atmosphere GasSymbolApproximate % Nitrogen N2 78.6 Oxygen O2 20.9 Carbon Dioxide CO2 0.04 Water Vapor H2O 0.46 Unit 1 - Objective 1

  4. Objective 2 Define partial pressure and be able tocompute 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 pressuresproduces 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 = 0.209 X 760 mmHg. This gives an oxygen partial pressure (PO2) of: 158.84 (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 = 0.0004 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 internalrespiration using short definitions. Unit 1 - Objective3

  10. Definition of Pulmonary Ventilation Pulmonary ventilation is the exchange of airbetween 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 exchangebetween 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. Objective 5 Name the ways carbon dioxide and oxygen are transported by the blood. Unit 1 - Objective 5

  18. Carbon Dioxide Transport MethodPercentage Dissolved in Plasma 7 - 10 % Chemically Bound to Hemoglobin in RBC’s 20 - 30 % As Bicarbonate Ion in Plasma 60 -70 % Unit 1 - Objective5

  19. Oxygen Transport Method Percentage Dissolved in Plasma 1.5 % Combined with Hemoglobin 98.5 % 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. O2 + Hb HbO2 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: Unit 1 - Objective 6

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

  23. CO2 + H2 0 H2 CO3 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: 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 tissuecapillaries, 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 pulmonarycapillaries, they take in bicarbonate and release carbon dioxide. As bicarbonate (-1) shifts into the RBC, chloride (-1) shifts outof 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: PO2Percent 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: PO2Percent Saturation 100 mm Hg 98 40 mm Hg 75 26 mm Hg 50 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 ponscontains the pneumotaxicrespiratory center and the apneusticrespiratory center. Both of these centers are considered secondary respiratorycenters. This means they do not set the basic respiratory rhythm. Instead, they modify the basic respiratory rate. Themedullacontains the medullary respiratorycenter 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 pneumotaxicrespiratory center inhibits inhibits inspiratory time and increases breaths per minute. The apneusticrespiratory center has not been clearlydefined, but, is postulated to prolong inspiratory time and reduces breaths per minute. Themedullary respiratorycenter 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

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