Final answer:
The statement about muscarinic and nicotinic cholinergic receptors is a. true. These receptors have different roles and characteristics in the nervous system, responding to the neurotransmitter acetylcholine.
Step-by-step explanation:
The statement that cholinergic receptors are muscarinic or nicotinic, with muscarinic receptors being able to be excitatory or inhibitory and affect glands, the heart muscle, and heart rate, and nicotinic receptors being found in all postsynaptic autonomic neurons and the adrenal medulla is true.
Both muscarinic and nicotinic receptors bind to acetylcholine (ACh) but are distinguished by other molecules like nicotine and muscarine that bind to them, with no cross-reactivity. While the nicotinic receptor acts as a ligand-gated cation channel that typically results in depolarization, the muscarinic receptor is a G protein-coupled receptor that can have a variety of effects, not exclusively depolarization, on the postsynaptic cell.