“During exercise, activation of beta 2 adrenergic receptors on skeletal muscle cells causes more blood to reach this area of the body.” True or False? Provide reasons (3 marks)
Answer:
True.
Reasons (3 marks):
(1 mark) Beta-2 adrenergic receptors on vascular smooth muscle (including arterioles supplying skeletal muscle) activate Gs proteins that increase intracellular cAMP, causing smooth muscle relaxation and vasodilation.
(1 mark) Vasodilation of arterioles and precapillary sphincters in skeletal muscle lowers vascular resistance locally, increasing blood flow to meet the metabolic demands of exercising muscle.
(1 mark) During exercise, sympathetic activity combined with circulating epinephrine preferentially activates beta-2 receptors in skeletal muscle vasculature, redirecting blood flow from nonessential regions to active muscles.
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