RESPIRATORY PHYSIOLOGY
Practice Questions: Blood Gas Transport

BLOOD GAS TRANSPORT QUESTIONS

1. Cyanosis (a bluish color of the skin and mucous membranes) indicates a higher than normal blood concentration of

A. carbon dioxide
B. carbon monoxide
C. hydrogen ion
D. diphosphogycerate (DPG)
E. reduced hemoglobin

2. As blood passes through systemic capillaries, what happens to the affinity of hemoglobin for oxygen and what happens to the Hb-O2 dissociation curve?

A. Hb affinity for O2 increases and the dissociation curves shifts to the left
B. Hb affinity for O2 increases and the dissociation curves shifts to the right
C. Hb affinity for O2 decreases and the dissociation curves shifts to the left
D. Hb affinity for O2 decreases and the dissociation curves shifts to the right
E. neither Hb affinity for O2 nor the Hb-O2 dissociation curve change

3. Suppose a person has a genetic defect causing him to continue to produce fetal hemoglobin (rather than normal hemoglobin) throughout adult life. What would be the expected systemic arterial oxygen partial pressure and saturation (compared to a normal person)?

A. higher Pa-O2 and higher Hb O2 saturation
B. higher Pa-O2 but lower Hb O2 saturation
C. lower Pa-O2 but higher Hb O2 saturation
D. lower Pa-O2 and lower Hb O2 saturation
E. normal Pa-O2 but higher Hb O2 saturation

4. Compared with systemic arterial blood, pulmonary arterial blood has a higher

A. oxygen content
B. pH
C. bicarbonate ion concentration

D. Hb concentration
E. none of the above

5. As blood passes through systemic capillaries, the enzyme carbonic anhydrase catalyzes

A. conversion of dissolved CO2 to carbonic acid
B. conversion of carbonic acid to bicarbonate ion
C. conversion of gaseous CO2 to dissolved CO2
D. binding of carbon dioxide to hemoglobin, thus displacing oxygen
E. all of the above

6. What would be the expected systemic arterial oxygen content of a normal person inhaling pure oxygen (100% O2) for an hour or so?

A. 100 ml O2 / dl blood (100 ml blood)
B. 40 ml O2 / dl blood (100 ml blood)
C. 22 ml O2 / dl blood (100 ml blood)
D. 11 ml O2 / dl blood (100 ml blood)
E. none of the above, since pure oxygen is toxic and would cause death within the hour

7. An oxyhemoglobin saturation of mixed systemic venous blood of 25% for a person at rest is

A. above normal
B. below normal
C. within the normal range

8. A hemoglobin concentration in systemic venous blood of 20 gm/dl blood is

A. above normal
B. below normal
C. within the normal range