Certified Transport Registered Nurse Certification Practice Exam

Which physiological response is typically seen at elevations above 10,000 ft?

1. Decreased heart rate

2. Increased diuresis

3. Decreased respiratory effort

4. Increased blood flow to the brain

The correct answer is: Increased diuresis

When ascending to elevations above 10,000 feet, the body undergoes a series of physiological adaptations to cope with reduced atmospheric pressure and lower oxygen levels. Increased diuresis, or heightened urine production, is a common response in this scenario. As the body attempts to acclimatize to the altitude, increased levels of hormones like atrial natriuretic peptide (ANP) are triggered in response to changes in blood volume and pressure. This leads to increased sodium and water excretion by the kidneys, resulting in greater urine output. This response serves to reduce blood volume to counteract potential increases in blood pressure caused by the initial hypoxic environment. It is a protective mechanism designed to help maintain homeostasis in the face of the physiological stressors encountered at high altitudes. In summary, increased diuresis reflects the body's adaptive response to manage fluid balance and pressure changes associated with high-altitude conditions, making it the correct answer regarding typical physiological responses at elevations above 10,000 feet.