APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Within the parasympathetic nervous system alone, the postganglionic neuron releases acetylcholine as its primary neurotransmitter.

Detailed explanation-2: -The PNS uses acetylcholine as its neurotransmitter for both pre-and postganglionic neurons activating muscarinic receptors. This differs from the SNS, which uses norepinephrine, which acts on adrenergic receptors, as the primary neurotransmitter for most postganglionic neurons.

Detailed explanation-3: -Acetylcholine is a neurotransmitter that plays a role in memory, learning, attention, arousal and involuntary muscle movement. Medical conditions associated with low acetylcholine levels include Alzheimer’s disease and myasthenia gravis.

Detailed explanation-4: -Parasympathetic nerves traveling within the vagus nerve release acetylcholine to act upon M2 and M3 muscarinic receptors on airway smooth muscle. The nerve terminals also express autoinhibitory M2 muscarinic receptors that respond to released acetylcholine to inhibit further neurotransmitter release.