Question

What anatomical mechanism is involved in causing a person to blush?

a) blood flow to the skin is increased by parasympathetic stimulation
b) sympathetic stimulation relaxes vessel walls, increasing blood flow to the skin
c) parasympathetic stimulation decreases skin muscle tone, allowing blood to pool at the surface
d) sympathetic stimulation increases respiratory oxygen uptake, making the blood brighter red

Answer 1

Blushing is caused by the dilation of blood vessels in the face due to sympathetic stimulation, which relaxes the vessel walls and increases blood flow to the skin. The correct answer is option b.

Step-by-step explanation:

The anatomical mechanism involved in causing a person to blush is related to the sympathetic nervous system, which is part of the autonomic nervous system that controls involuntary body functions. Specifically, when a person blushes, sympathetic stimulation causes the dilation of blood vessels in the face. This dilation is due to the relaxation of the smooth muscles in the vessel walls, which increases blood flow to the skin, causing the reddening characteristic of blushing. Thus, the correct answer is b) sympathetic stimulation relaxes vessel walls, increasing blood flow to the skin.