2.  the diaphragm  the abdominal muscles  atmospheric pressure  the external intercostal muscles

3.  occurs by simple diffusion  Diffusion requires a concentration gradient.  Concentration (or pressure) of O2 in the alveoli must be kept at a higher level than in the blood & the concentration (or pressure) of CO2 in the alveoli must be kept at a lower lever than in the blood.

4. The walls of alveoli- coated with water film creates surface tension Pulmonary Surfactant Role Pulmonary Surfactant Surfactant decreases surface tension which Surfactant decreases surface tension which : – increases pulmonary compliance (reducing the effort needed to expand the lungs) – reduces tendency for alveoli to collapse

6. 1. Exchange of O2 & CO2 between external environment & the cells of the body 2. Efficient because alveoli and capillaries have very thin walls & are very abundant (your lungs have about 300 million alveoli with a total surface area of about 75 square meters)

7.  constricted; dilate  dilated; constrict  mucus-filled; empty of mucus  both a and c

8. 1.The partial pressure exerted by each gas in a mixture equals the total pressure times the fractional composition of the gas in the mixture. 2.Total atmospheric pressure (at sea level) is 760 mm Hg 3.Air is about 21% oxygen 2.the partial pressure of oxygen in the air is 0.21 times 760 mm Hg or 160 mm Hg.

9. Alveoli PO2 = 100 mm Hg PCO2 = 40 mm Hg Alveolar capillaries Entering the alveolar capillaries PO2 = 40 mm Hg (relatively low because this blood has just returned from the systemic circulation & has lost much of its oxygen) PCO2 = 45 mm Hg (relatively high because the blood returning from the systemic circulation has picked up carbon dioxide)

11. Entering the systemic capillaries PO2 = 100 mm Hg PCO2 = 40 mm Hg Leaving the systemic capillaries PO2 = 40 mm Hg PCO2 = 45 mm Hg Body cells (resting conditions ) PO2 = 40 mm Hg PCO2 = 45 mm Hg

12. Oxygen is carried in blood: 1 - bound to hemoglobin (98.5% of all oxygen in the blood) 2 - dissolved in the plasma (1.5%)

13.  one  two  three  four

15. Amount of Oxygen Hb hold on oxygen is reduced Amount of Oxygen Hb hold on oxygen is increased

16. Temperature- Increasing the temperature denatures the bond between oxygen and hemoglobin, which increases the amount of oxygen and hemoglobin and decreases the concentration of oxyhemoglobin. pH- A decrease in pH (increase in acidity) by addition of carbon dioxide: oxygen to be given up as oxygen pressure increases.

17. A swimmer, in an attempt to decrease PB time for a particular event, routinely hyperventilates before a race, as he says “to sock more oxygen into my lungs so I can swim longer without having to breathe. What is this swimmer fundamentally misunderstanding about oxygen loading? How is this swimmer jeopardizing not only his time, but his life?

18. 1. bicarbonate (HCO3) - 60% formed when CO2 (released by cells making ATP) combines with H2O (due to the enzyme in red blood cells called carbonic anhydrase) as shown in the diagram below 2 - carbaminohemoglobin - 30% formed when CO2 combines with hemoglobin (hemoglobin molecules that have given up their oxygen) 3 - dissolved in the plasma - 10% CO2 + H20 -----> H2CO3 -----> HCO3 - + H +

19. Diffusion in the Tissues: pg 833 Know this!

20. Diffusion in the Lungs pg 833 Know this!

21.  provide chlorine to the enzyme carbonic anhydrase.  counterbalance the exodus of bicarbonate ions from red blood cells.  counterbalance the exodus of H + from red blood cells.  convert chloride ions to bicarbonate ions.

22. As plasma pH decreases, hemoglobin's O 2 affinity will _________. You begin to hyperventilate! What happens to your plasma Pco 2 ? What about your plasma pH? decreaseincrease decrease Select the correct statement about O 2 transport in the blood. 1.During normal activity, a molecule of Hb returning to the lungs contains one molecule of oxygen 2.As pH decreases, oxygen's affinity for Hb increases 3.A 30% oxygen saturation level of blood returning to the lungs might indicate a higher activity level than normal 4.All of the above 5.None of the above 3