Scenario C: Bill is a healthy guy who has gotten lost in the wilderness, he's been climbing a cliff to try to get home. His legs (and some other muscles) are burning huge amounts of ATP (total metabolic rate has increased to around 7 times basal). His cardiac output has risen to five times the basal rate. His respiratory rate has increased from 10 breath/min at rest to about 20 breath/min. His tidal volume has risen from 700 ml at rest to about 1525 ml. He weighs about 70 kg (~150 lb). If no other control actions or reflexes occur, what will be the effect on (compared to rest values) 1. PO2 at most alveoli: .
a) increased by 30 mmHg,
b) largely unchanged,
c) decreased by 30 mmHg
2. PO2 at the left atrium: .
a) increased by 30 mmHg,
b) largely unchanged,
c) decreased by 30 mmHg
3. PO2 at the right ventricle (mixed venous PO2): .
a) increased by 10 mmHg,
b) largely unchanged,
c) decreased by 10 mmHg
4. Oxygen delivery to the systemic tissues :.
a) decreased by 20%
b) largely unchanged
c) increased by 20%
d) increased proportionally to increase in cardiac output
e) increased proportionally to increase in metabolism