A healthy 25-year-old man is undergoing an exercise stress test. Which of the following is most likely to occur in this man’s skeletal muscle during exercise?
Decreased capillary hydrostatic pressure
Decreased metabolite concentration
Increased arteriolar diameter
Increased oxygen concentration
Increased vascular resistance
Correct answer
Increased arteriolar diameter
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correct answer: C
As skeletal muscle activity increases, the oxygen demand increases. The vascular supply to the area responds by dilating the arterioles in order to bring in more blood and supply the increased oxygen demand.
Choice A is incorrect because hydrostatic pressure in the capillaries is increased as blood flow increases.
Choice B is incorrect because contracting skeletal muscle will produce metabolites and release them into the capillaries. Choice D is incorrect because contracting muscle cells will take up oxygen from the capillaries.
Choice E is incorrect because the vascular supply to the muscle is increased as the arterioles vasodilate, therefore vascular resistance decreases.