ch 23 pt 2

The partial pressure of oxygen in the interstitial space of peripheral tissues is approximately A) 40 mm Hg. B) 45 mm Hg. C) 50 mm Hg. D) 70 mm Hg. E) 100 mm Hg.

A) 40 mm Hg.

Which of the following decreases respiratory efficiency? A) decreased blood flow B) increased surface area C) increased partial pressure gradients D) increased gas solubility E) decreased diffusion distance

A) decreased blood flow

When does oxyhemoglobin form during respiration? A) during external respiration B) immediately after carbon dioxide enters the blood C) when the chloride shift occurs D) during pulmonary ventilation E) during internal respiration

A) during external respiration

The partial pressure of oxygen in atmospheric air at sea level is A) greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest. B) less than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest. C) equal to the partial pressure of oxygen in atmospheric air at the top of Mt. Everest. D) equal to the sum of partial pressures from carbon dioxide and nitrogen. E) equal to the partial pressure of carbon dioxide in atmospheric air at the top of Mt. Everest.

A) greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.

Each 100 ml of blood leaving the alveolar capillaries carries away roughly ________ ml of oxygen. A) 10 B) 20 C) 30 D) 50 E) 75

B) 20

The partial pressure of carbon dioxide in the interstitial space of peripheral tissues is approximately A) 35 mm Hg. B) 45 mm Hg. C) 55 mm Hg. D) 70 mm Hg. E) 100 mm Hg.

B) 45 mm Hg.

The partial pressure of carbon dioxide in venous blood is approximately A) 40 mm Hg. B) 45 mm Hg. C) 50 mm Hg. D) 70 mm Hg. E) 100 mm Hg.

B) 45 mm Hg.

The effect of pH on hemoglobin saturation is known as the A) Bainbridge reflex. B) Bohr effect. C) pulmonary reflex. D) respiratory effect. E) Hering-Breuer reflex.

B) Bohr effect.

Most of the oxygen transported by the blood is A) dissolved in plasma. B) bound to hemoglobin. C) in ionic form as solute in the plasma. D) bound to the same protein as carbon dioxide. E) carried by white blood cells.

B) bound to hemoglobin.

The most important chemical regulator of respiration is A) oxygen. B) carbon dioxide. C) bicarbonate ion. D) sodium ion. E) hemoglobin.

B) carbon dioxide.

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

B) decreased pH

A 10 percent increase in the level of carbon dioxide in the blood will A) decrease the rate of breathing. B) double the respiratory rate. C) decrease pulmonary ventilation. D) decrease the alveolar ventilation rate. E) decrease the vital capacity.

B) double the respiratory rate.

The term hypercapnia refers to A) the cessation of breathing. B) elevated PCO2. C) elevated PO2. D) an increase in pH. E) labored breathing.

B) elevated PCO2.

160) Low pH alters hemoglobin structure so that oxygen binds less strongly to hemoglobin at low PO2. This increases the effectiveness of A) external respiration. B) internal respiration. C) carbon dioxide transport. D) hemoglobin synthesis. E) acid-base balance.

B) internal respiration.

Hemoglobinʹs affinity for oxygen when the BPG level is high is A) greater than hemoglobinʹs affinity for oxygen when the BPG level is low. B) less than hemoglobinʹs affinity for oxygen when the BPG level is low. C) equal to hemoglobinʹs affinity for oxygen when the BPG level is low. D) equal to hemoglobinʹs affinity for oxygen when pH is low. E) equal to hemoglobinʹs affinity for oxygen when pH is high.

B) less than hemoglobinʹs affinity for oxygen when the BPG level is low.

The apneustic centers of the pons A) inhibit the pneumotaxic and inspiratory centers. B) provide stimulation to the inspiratory center. C) monitor blood gas levels. D) alter chemoreceptor sensitivity. E) generate the gasp reflex.

B) provide stimulation to the inspiratory center.

The chloride shift occurs in order to A) force oxygen out of the blood and into tissues. B) transport bicarbonate ions into the blood plasma. C) produce salt for the cytosol of blood cells. D) produce carbonic acid. E) pump hydrochloric acid out of gastric cells.

B) transport bicarbonate ions into the blood plasma.

At a PO2 of 70 mm Hg and normal temperature and pH, hemoglobin is ________ percent saturated with oxygen. A) 10 B) 25 C) 50 D) 75 E) more than 90

E) more than 90

If PO2 increases A) saturation goes down and hemoglobin gives away oxygen. B) hemoglobin stores oxygen. C) hemoglobin gives away oxygen. D) saturation goes up. E) saturation goes up and hemoglobin stores oxygen.

E) saturation goes up and hemoglobin stores oxygen.

159) The percent of oxygen saturation of hemoglobin when the temperature is 38 degrees centigrade is A) greater than the percent of oxygen saturation of hemoglobin when the temperature is 43 degrees centigrade. B) less than the percent of oxygen saturation of hemoglobin when the temperature is 43 degrees centigrade. C) equal to the percent of oxygen saturation of hemoglobin when the temperature is 43 degrees centigrade. D) equal to the percent of oxygen saturation of hemoglobin when the temperature is 20 degrees centigrade. E) equal to the percent of oxygen saturation of hemoglobin when BPG levels are high.

A) greater than the percent of oxygen saturation of hemoglobin when the temperature is 43

170) All of the following provide chemoreceptor input to the respiratory centers of the medulla oblongata except the A) olfactory epithelium. B) medullary chemoreceptors. C) aortic body. D) carotid body. E) central chemoreceptors.

A) olfactory epithelium.

The partial pressure of carbon dioxide is greatest in A) venous blood. B) alveolar air. C) expired air. D) inspired air. E) arterial blood.

A) venous blood.

Under quiet conditions, blood returning to the heart retains about ________ of its oxygen content. A) 25 percent B) 50 percent C) 75 percent D) 90 percent E) 100 percent

C) 75 percent

A SCUBA diver has been deep underwater and suddenly rises to the surface too fast. Why does the diver get decompression sickness? A) Pressure decreases and carbon dioxide rushes into cells. B) Pressure changes too fast and the carbon dioxide in the blood forms bubbles. C) Pressure decreases too fast and nitrogen gas in the blood forms bubbles. D) The gas in the SCUBA tank had too much pressure and rapid ascent forces too much air into the blood. E) Pressure increases too fast and too much oxygen enters the blood and forms bubbles.

C) Pressure decreases too fast and nitrogen gas in the blood forms bubbles.

Most of the carbon dioxide in the blood is transported as A) solute dissolved in the plasma. B) carbaminohemoglobin. C) bicarbonate ions. D) solute dissolved in the cytoplasm of red blood cells. E) carbonic acid.

C) bicarbonate ions.

Carbon dioxide and water combine to form A) hydrochloric acid. B) oxygen. C) carbonic acid. D) carbaminohemoglobin. E) nitric acid.

C) carbonic acid.

Which of these factors does not affect hemoglobinʹs affinity for oxygen? A) RBC metabolic activity B) temperature C) electrolyte balance D) the PO2 of blood E) blood pH

C) electrolyte balance

Total alveolar surface area is reduced in A) lung cancer. B) atelectasis. C) emphysema. D) pneumothorax. E) asthma.

C) emphysema.

Henryʹs law states that A) gas volume and temperature are directly proportional. B) gas volume and pressure are inversely proportional. C) the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure. D) in a mixture of gases such as air, the total pressure is the sum of the individual partial pressures of the gases in the mixture. E) gas pressure is inversely proportional to gas volume.

C) the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure.

Which is not a reason gas exchange is efficient at the blood air barrier? A) Partial pressure differences are substantial. B) Distance is short. C) Surface area is large. D) Gap junctions facilitate fast movement. E) Gases are lipid soluble.

D) Gap junctions facilitate fast movement.

Each of the following factors affects the rate of external respiration except the A) PO2 of the alveoli. B) PCO2 of the blood. C) thickness of the respiratory membrane. D) PN2 of the alveoli. E) solubility of oxygen in plasma.

D) PN2 of the alveoli.

Daltonʹs law states that A) gas volume and temperature are directly proportional. B) gas volume and pressure are inversely proportional. C) the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure. D) in a mixture of gases such as air, the total pressure is the sum of the individual partial pressures of the gases in the mixture. E) gas pressure is inversely proportional to gas volume.

D) in a mixture of gases such as air, the total pressure is the sum of the individual partial pressures of the gases in the mixture.

Factors affecting the release of oxygen from hemoglobin can be visualized by using a A) spirograph. B) pulmonary volume chart. C) respiratory cycle chart. D) oxygen-hemoglobin saturation curve. E) blood gas analysis.

D) oxygen-hemoglobin saturation curve.

The partial pressure of oxygen in arterial blood is approximately A) 40 mm Hg. B) 45 mm Hg. C) 50 mm Hg. D) 70 mm Hg. E) 100 mm Hg.

E) 100 mm Hg.

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.

E) It causes RBCs to swell.

For maximum loading of hemoglobin with oxygen at the lungs, the A) PCO2 should be high. B) pH should be slightly acidic. C) PO2 should be about 70 mm Hg. D) BPG levels in the red blood cells should be high. E) PO2 should be as high as possible.

E) PO2 should be as high as possible.