The parasympathetic ANS utilizes acetylcholine at which synapses?

• A. All
• B. Only at some synapses
• C. Only at neuromuscular junctions
• D. None

Answer: (A)

The main idea is that the parasympathetic branch uses acetylcholine at every synapse in its pathway. Preganglionic neurons release acetylcholine onto nicotinic receptors in parasympathetic ganglia, and the postganglionic parasympathetic neurons are also cholinergic, releasing acetylcholine onto muscarinic receptors on the target organs. So acetylcholine is used at both the ganglionic synapse and the effector-organ synapse. That’s why all of the parasympathetic synapses utilize acetylcholine. The other options don’t fit because it’s not limited to just some synapses, and it’s not correct to say it’s only at neuromuscular junctions (that refers to the somatic motor system and skeletal muscle), nor is it correct to say none.