Ch 23: Part 15

Under quiet conditions, blood returning to the heart retains about ________ of its oxygen content.

75 percent

Which of the following statements about the chloride shift is false? A) It involves a movement of chloride ion into RBCs. B) It depends on the chloride-bicarbonate countertransporter. C) It involves a movement of bicarbonate ions into the plasma. D) It is driven by a rise in PCO2. E) It causes RBCs to swell.

It causes RBCs to swell.

Low pH alters hemoglobin structure so that oxygen binds less strongly to hemoglobin at low PO2. This increases the effectiveness of

internal respiration.

The percent of oxygen saturation of hemoglobin when the temperature is 38 degrees centigrade is

greater than the percent of oxygen saturation of hemoglobin when the temperature is 43 degrees centigrade.

Each 100 ml of blood leaving the alveolar capillaries carries away roughly ________ ml of oxygen.

20

For maximum loading of hemoglobin with oxygen at the lungs, the

PO2 should be as high as possible.

Most of the carbon dioxide in the blood is transported as

bicarbonate ions.

Most of the oxygen transported by the blood is

bound to hemoglobin.

Which of the following factors would increase the amount of oxygen discharged by hemoglobin to peripheral tissues? A) decreased temperature B) decreased pH C) increased tissue PO2 D) decreased amounts of BPG E) decreased temperature and decreased amounts of BPG

decreased pH

Hemoglobin's affinity for oxygen when the BPG level is high is

less than hemoglobin's affinity for oxygen when the BPG level is low.