Blushing occurs when sympathetic stimulation of facial blood results in their di
ID: 81535 • Letter: B
Question
Blushing occurs when sympathetic stimulation of facial blood results in their dilation. This explanation seems almost counterintuitive since sympathetic stimulation is usually associated with vasoconstriction. It can be accounted for in part by the fact that the facial blood vessels are equipped with beta-adrenergic receptors coupled to _______ proteins, which stimulate adenylyl cyclase while other blood vessels are equipped with alpha-adrenergic receptors coupled to _________ proteins, which inhibit adenylyl cyclase. Both types of receptors respond to ________.
A. Gi, Gq, acetylcholine. C. Gs, Gi, norepinephrine
B. Gq, Gs, norepinephrine D. Gs, Gi, acetylcholine
Explanation / Answer
C. Gs,Gi, Norepinephrine
beta adrenergic receptors bind to Gs proteins
Alpha adrenergic receptors bind to Gi protein