Acetylcholine is a chemical neurotransmitter of which nervous system?

Acetylcholine serves as a key neurotransmitter in both the parasympathetic nervous system and the somatic nervous system, playing a pivotal role in the transmission of signals between neurons and muscles. In the context of the parasympathetic nervous system, acetylcholine is responsible for promoting rest-and-digest responses, which include slowing the heart rate, increasing intestinal and gland activity, and relaxing sphincter muscles. This action is primarily facilitated through the binding of acetylcholine to its receptors in target organs and tissues, resulting in the modulation of various physiological functions.

In the somatic nervous system, acetylcholine is integral to the activation of skeletal muscles. It is released at neuromuscular junctions, where it binds to receptors on muscle fibers, leading to muscle contraction. Although this is a crucial function, the question specifically asks about its role in a particular type of nervous system, which aligns more directly with its dominant function in the parasympathetic nervous system regarding autonomic regulation and control of involuntary functions.

Thus, acetylcholine's role as a neurotransmitter that primarily mediates the parasympathetic nervous system’s effects establishes it clearly as the correct choice in this context.