Question

ch 20 quiz
10
during exercise, the adrenal medulla and sympathetic nerves cause which of the following to occur?
multiple choice
○ precapillary sphincters constrict in response to muscle metabolites such as lactic acid, co₂, and adenosine
○ arterioles dilate in response to epinephrine and norepinephrine
○ muscles contract to compress the blood vessels

Explanation:

The question is about the physiological responses during exercise related to the adrenal medulla and sympathetic nerves, which falls under the subfield of Biology (specifically human physiology) in Natural Science. To solve, we analyze each option:

• Option 1: Precapillary sphincters constrict due to muscle metabolites (like lactic acid, CO₂) – this is local metabolic control, not direct sympathetic/adrenal medulla action.
• Option 2: Arterioles dilate due to epinephrine/norepinephrine – the adrenal medulla releases epinephrine, and sympathetic nerves release norepinephrine. These hormones/neurotransmitters cause arterioles (especially in muscles) to dilate during exercise to increase blood flow.
• Option 3: Muscles contract to compress vessels – muscle contraction compresses vessels, but this is a mechanical effect, not direct from adrenal medulla/sympathetic nerves' chemical signaling.

So the correct option is the one stating arterioles dilate in response to epinephrine and norepinephrine. (Assuming the second option is this; due to partial text, but based on physiology, this is the mechanism.)

Answer:

(Assuming the second option is "Arterioles dilate in response to epinephrine and norepinephrine")
B. Arterioles dilate in response to epinephrine and norepinephrine (or the corresponding option label with this text)