Question

In response to lower PO2 at altitude, what happens to the body

a) Increased blood oxygenation
b) Decreased heart rate
c) Increased red blood cell production
d) Decreased respiratory rate

Answer 1

The body compensates for lower PO2 at high altitudes by increasing red blood cell production, which enhances oxygen transport capability despite lower oxygen saturation of hemoglobin.

Step-by-step explanation:

In response to lower partial pressure of oxygen (PO2) at altitude, the body primarily responds by increasing red blood cell production. This happens because, at high altitude, the partial pressure of oxygen decreases, making it more difficult for the body to achieve the same level of oxygen saturation as at sea level. The kidneys respond to lower tissue levels of oxygen by producing the hormone erythropoietin (EPO), which stimulates the production of erythrocytes (red blood cells). As a result, with more red blood cells in circulation, there is more hemoglobin available to transport the available oxygen despite lower saturation of each hemoglobin molecule. This acclimatization process helps the individual to partake in physical exertion without developing Acute Mountain Sickness (AMS).