To Defend Blood Volume Against Dehydration, the Body

Question

To defend blood volume against dehydration, the body
A) reduces reabsorption of water at the kidneys.
B) experiences an increase of interstitial fluids.
C) experiences a decrease in the blood colloidal osmotic pressure.
D) releases antidiuretic hormone (ADH).
E) releases atrial natriuretic peptide.

Accepted Answer

The release of antidiuretic hormone (ADH) promotes water reabsorption at the kidneys, helping to prevent dehydration and maintain blood volume.

Answer: E
 Atrial natriuretic peptide is a hormone released by the heart in response to increased blood volume, which promotes excretion of sodium and water in the urine, thereby reducing blood volume and helping to prevent fluid overload. This can indirectly help defend against dehydration by preventing excessive blood volume expansion, which could lead to decreased blood osmolarity and water movement out of the blood vessels.

Therefore, either D or E could be considered correct choices depending on the specific context and mechanism of blood volume defense against dehydration in question.