There are two types of fibers, classified based on what neurotransmitter they release
i. Cholinergic fibers release neurotransmitter ACh
- All ANS preganglionic axons
- All parasympathetic postganglionic axons at effector synapse
ii. Adrenergic fibers release neurotransmitter NE
- Most sympathetic postganglionic axons
- Exception: sympathetic postganglionic fibers secrete ACh sweat glands

Critical Thinking: Would preganglionic fibers in the parasympathetic division be considered cholinergic or adrenergic fibers?