Final answer:
Neurons secreting acetylcholine are cholinergic, and those secreting norepinephrine are adrenergic. Parasympathetic neurons usually release ACh, whereas sympathetic neurons mainly release norepinephrine. Norepinephrine can act as both a neurotransmitter and a hormone, depending on where it's released.
Step-by-step explanation:
Neurons that secrete acetylcholine are described as cholinergic neurons, whereas those that secrete norepinephrine are called either adrenergic neurons. This classification is based on the type of neurotransmitter these neurons release at the synapse when connecting with a target organ or tissue.
In the autonomic nervous system, parasympathetic neurons typically release acetylcholine (ACh) and therefore have cholinergic synapses. The postganglionic fibers of the sympathetic division predominantly release norepinephrine, making them adrenergic.
To further clarify, signaling molecules can be classified as neurotransmitters, which are released at synapses, or hormones, which are released into the bloodstream. While acetylcholine is considered a neurotransmitter because it is primarily released by axons at synapses, norepinephrine can fit into both categories: it acts as a neurotransmitter when released by postganglionic sympathetic fibers and as a hormone when released by the adrenal medulla.