Question

Preganglionic sympathetic fibres are
A. Adrenergic
B. Cholinergic
C. Synergic
D. Hypertonic

Answer 1

In the autonomic nervous system, fibers from the CNS to the ganglion are known as preganglionic fibers. All preganglionic fibers, whether they are in the sympathetic division or in the parasympathetic division.

Complete answer:
Adrenergic nerve fiber is a type of neuron for which the neurotransmitter is noradrenaline or dopamine, adrenaline. These neurotransmitters are released at a specific location known as the synapse, which is the junction between the dendrite and the axon of one nerve cell.
-Cholinergic neuron secretes acetylcholine and is found in central and peripheral nervous systems. The preganglionic neurons in the sympathetic and parasympathetic arms of the autonomic nervous system are cholinergic. In postganglionic fibers all parasympathetic postganglionic neurons are cholinergic, but only a small number of sympathetic postganglionic neurons are cholinergic.
Hence, the correct answer is option B, i.e., Cholinergic.

Additional information:
In the autonomic nervous system (ANS), the fibres from the central nervous system to the ganglion are known as preganglionic fibres. All preganglionic fibres if it is a sympathetic nervous system or in the parasympathetic nervous system are cholinergic that means they use acetylcholine as their neurotransmitter. The autonomous nervous system is very unique in that it requires two neuron efferent sequential pathways; the preganglionic neuron should first cross the synapse onto a postganglionic neuron before it goes to the target organ.

Note: The parasympathetic division of the sympathetic division is preganglionic fibers which are cholinergic. For neurotransmission these fibers use acetylcholine and hence they are called cholinergic. The terminal knobs secrete and release the neurotransmitter when there is a conduction of impulse at the synaptic junctions.