anim_gas_exchange _answer_key.doc

Gas Exchange To complete this worksheet, select: Module: Gas Exchange and pH Balance Activity: Animations Title: Gas Exchange Introduction 1. a. Describe the respiratory system role with oxygen and carbon dioxide. The respiratory system is responsible for the movement of gases involved in cellular metabolism. b. Why is oxygen needed? Oxygen is needed because it is used up during the aerobic breakdown of glucose. c. What generates CO2? Carbon dioxide arises from the aerobic metabolism of glucose . 2. Define the three important continuous physiological processes that are responsible for the movement of oxygen and carbon dioxide. Ventilation - This is the movement of gases between the lungs and the atmosphere. Gas Exchange –this is the movement of gases into and out of the bloodstream. This occurs at the lungs and at the tissues. Gas Transport – This is the movement of gases via the blood stream to the organs and tissues of the body. Gas Exchange 3. Explain the correlation between gas pressure and concentration. The direction that a gas moves is dependent on the concentration of that gas. A gas within a compartment exerts a pressure, which is proportional to the concentration of that gas. More gas molecules exert a greater pressure. gas molecules will move down a gradient from higher pressure to lower pressure. 4. a. Define partial pressure. Each gas in a mixture of gases exerts its own pressure. The individual pressure of each gas In a mixture is called the partial pressure of that gas.. b. Describe how partial pressure determines movement of specific gas molecules in a mixture. A gas moves along the part of the pressure gradient determined by its own concentration. Gas molecules will move from higher concentrations to lower concentrations. c. Why would oxygen diffuse into this blood vessel while carbon dioxide diffuses out? Oxygen diffuses into the blood vessels because the partial pressure of oxygen is greater in the alveoli than in he blood stream. Oxygen moves down its concentration gradient. Carbon dioxide moves out of the blood into the alveoli because the partial pressure of carbon dioxide is greater in the blood than in the alveoli and carbon dioxide will move down its concentration gradient. Contrast External and Internal respiration. Internal respiration is the gas exchange between the blood and the systemic cell and tissue compartments. The gas exchange between the alveolar spaces in the lungs and the blood in the pulmonary capillaries is external respiration. External Respiration 6. Define external respiration. This is the gas exchange between the alveolar spaces in the lungs and the blood capillaries. What is the critical function of ventilation? Ventilation brings air, rich in oxygen, into the alveolar spaces in the lung and alveolar air rich in carbon dioxide out into the atmosphere. 8. a. Contrast the P02 (oxygen partial pressure) in the lungs (alveoli) and in the surrounding blood capillaries. Air in the alveolar space has a high P02 and air in the pulmonary capillary has a low P02. b. Contrast the PCO2 (carbon dioxide partial pressure) in the lungs (alveoli) and in the surrounding blood capillaries. Air in the alveolar spaces has a low PCO2 and blood in the pulmonary capillary has a high PCO2. c. Gas diffusion is dependent upon the partial pressure of gasses. Explain the movement of the following gasses between lung alveoli and blood capillaries as a function of their relative partial pressures in each location. Oxygen -Oxygen moves from the alveolar compartment to the capillary compartment as determined by its partial pressure. Carbon Dioxide – Carbon dioxide moves from the capillary compartment to the alveolar compartment as determined by its partial pressure. Internal Respiration 9. Define internal respiration. Internal respiration is the gas exchange between the systemic blood capillaries and the tissue cells. 10. a. Contrast the P02 (oxygen partial pressure) in the blood capillaries and in the cells of the surrounding tissues. The blood near the tissues has a high P02 and each cell in the tissue compartment has a low P02. b. Contrast the PCO2 (carbon dioxide partial pressure) in the blood capillaries and in the cells of the surrounding tissues. The blood near the tissues has a low PCO2 and each cell in the tissue compartment has a high PCO2. c. Explain the movement of the following gasses between blood capillaries and tissue cells as a function of their relative partial pressures in each location. Oxygen -Oxygen will move from the capillary blood compartment to the cell compartment as dictated by its partial pressure gradient. Carbon Dioxide – Carbon dioxide will move from the cell compartment to the blood in the capillary compartment as dictated by its partial pressure.