What is the physiological response to a decrease in atmospheric PO2, such as during altitude exposure?

What is the physiological response to a decrease in atmospheric PO2, such as during altitude exposure?

• A. Decrease in respiratory rate
• B. Increase in respiratory rate
• C. Retention of CO2
• D. Decrease in EPO production

Answer: (B)

During exposure to decreased atmospheric partial pressure of oxygen (PO2), such as at higher altitudes, the body responds by increasing the respiratory rate. This physiological adaptation occurs as the body attempts to enhance oxygen uptake in response to the reduced availability of oxygen in the environment. When atmospheric PO2 decreases, the oxygen saturation of hemoglobin in the blood also diminishes. In order to compensate for the lower oxygen levels, the brain's respiratory centers activate, leading to an increase in the rate and depth of breathing. This action promotes greater ventilation, thus facilitating a higher flow of air into the lungs and improving the diffusion of oxygen into the bloodstream. The increased respiratory rate helps to mitigate the effects of hypoxia, ensuring that tissues receive an adequate supply of oxygen despite the environmental challenges. Other physiological responses to altitude may include increased heart rate and elevated production of erythropoietin (EPO) to stimulate red blood cell production over time, but the immediate response is characterized by the increase in respiratory rate as the primary means of maintaining oxygen homeostasis.

During exposure to decreased atmospheric partial pressure of oxygen (PO2), such as at higher altitudes, the body responds by increasing the respiratory rate. This physiological adaptation occurs as the body attempts to enhance oxygen uptake in response to the reduced availability of oxygen in the environment.

When atmospheric PO2 decreases, the oxygen saturation of hemoglobin in the blood also diminishes. In order to compensate for the lower oxygen levels, the brain's respiratory centers activate, leading to an increase in the rate and depth of breathing. This action promotes greater ventilation, thus facilitating a higher flow of air into the lungs and improving the diffusion of oxygen into the bloodstream. The increased respiratory rate helps to mitigate the effects of hypoxia, ensuring that tissues receive an adequate supply of oxygen despite the environmental challenges.

Other physiological responses to altitude may include increased heart rate and elevated production of erythropoietin (EPO) to stimulate red blood cell production over time, but the immediate response is characterized by the increase in respiratory rate as the primary means of maintaining oxygen homeostasis.