Question

multiple choice question
what is the physiological benefit of an arteriovenous shunt in the fingers and toes?

it increases blood supply to these distal appendages
it remains closed and does not let blood pass
it reduces heat loss in cold weather
it increases the rate of nutrient exchange

Explanation:

To determine the correct answer, we analyze each option:

• "It increases blood supply to these distal appendages": Arteriovenous shunts in fingers/toes can open/close; when closed, blood goes to capillaries, but the shunt's role in cold is about heat loss, not increasing supply here. Eliminate.
• "It remains closed and does not let blood pass": Shunts can open (bypass capillaries) or close; this is incorrect as they do let blood pass in certain states. Eliminate.
• "It reduces heat loss in cold weather": In cold, arteriovenous shunts close, forcing blood through capillaries (which are near the surface less, reducing heat loss via radiation/convection from blood near skin). This matches physiological function.
• "It increases the rate of nutrient exchange": Nutrient exchange happens in capillaries; shunts bypass capillaries, so they don't increase nutrient exchange. Eliminate.

Answer:

C. It reduces heat loss in cold weather (assuming the options are labeled A - D with C as this option; adjust label based on original, but the correct option text is "It reduces heat loss in cold weather")