Final answer:
The answer to the question is true; acetylcholine is indeed the primary neurotransmitter released between preganglionic and postganglionic fibers within the parasympathetic division of the autonomic nervous system, affecting both nicotinic and muscarinic receptors.
Step-by-step explanation:
The statement that acetylcholine (ACh) is the major neurotransmitter released between the preganglionic and postganglionic fibers in the parasympathetic division of the autonomic nervous system is true. In both the sympathetic and parasympathetic divisions, all preganglionic fibers release ACh onto nicotinic receptors of the ganglionic neurons, leading to depolarization. In the parasympathetic system, the postganglionic fibers also release ACh, but the targets of these fibers have muscarinic receptors which are G protein-coupled receptors that can cause various effects on the postsynaptic membrane.
Within the parasympathetic nervous system, a rest-and-digest state is promoted, with preganglionic neurons originating in the brainstem and sacral spinal cord releasing ACh. These neurons project to terminal ganglia, usually very close to the target organs. The postganglionic neurons of the parasympathetic system, in turn, release ACh onto the target tissues, binding muscarinic receptors to induce rest-and-digest responses.