Question

When a person travels to areas of higher altitudes, his or her blood oxygen level decreases. After the person has been exposed to lower oxygen for a period of several weeks, they produce more red blood cells than normal.

A) This response occurs because the body adapts to lower oxygen levels by increasing red blood cell production to transport more oxygen.
B) When the body returns to its normal altitude and oxygen level, the excess red blood cells are broken down, and the production returns to normal.
C) The response occurs because the body stores excess oxygen at higher altitudes.
D) The body does not produce more red blood cells in response to lower oxygen levels.

Answer 1

The body compensates for lower oxygen levels at higher altitudes by increasing the production of red blood cells, stimulated by the hormone erythropoietin (EPO). This leads to increased oxygen transport capacity in the blood and is part of the acclimatization process.

Step-by-step explanation:

In high altitudes, where oxygen levels are lower, the body's oxygen saturation decreases, causing the kidneys to produce the hormone erythropoietin (EPO). EPO then stimulates the production of red blood cells to maintain adequate oxygen transport and meet the body's needs. Over time, this natural adaptation process, termed acclimatization, allows a person to partake in physical exertion without suffering from acute mountain sickness (AMS).

B) is also an accurate description of what happens when the body returns to normal altitude and oxygen level, the excess red blood cells are broken down, and the production levels return to normal. This is part of a negative feedback loop to maintain homeostasis.

Options C) and D) are incorrect. The body does not store excess oxygen at higher altitudes, nor does it ignore the need for increasing red blood cells in response to lower oxygen levels.