Question

Postganglionic nerve fibers of the sympathetic system are
a) Adrenergic
b) Cholinergic
c)Both A and B
d)None of the above

Answer 1

Hint: In the nervous system the fibers that extend from the ganglion and reach the effector organ are called postganglionic fibers. They are responsible for all the changes that occur in the effector organ which can be either through biochemical reaction or through neurotransmitter release.

Complete answer:
Postganglionic fibers are those fibers which are present in the nervous system and extend from the ganglion and reach to the effector organ. The postganglionic fibers in the sympathetic system are adrenergic and they use norepinephrine as their neurotransmitter. The postganglionic fibers which are present in the parasympathetic division are cholinergic and they use acetylcholine as their neurotransmitter. The postganglionic fibers are directly responsible for the changes that occur in the target organ through biochemical modulation and through neurotransmitter release. The preganglionic neurons release acetylcholine at the synapse end. This activates the receptors present in the postganglionic neurons. This stimulation makes them release the norepinephrine which helps in the activation of the adrenergic receptors present on the target tissues. This causes the effects that need to occur in the target tissues associated with the sympathetic system. sweat glands and chromaffin cells of the adrenal medulla are the exceptions in this case. The sweat glands release acetylcholine which is responsible for their activation of receptors.

So, the answer is ‘adrenergic’.

Note: The post-ganglionic fibres in the sympathetic system are adrenergic and they use norepinephrine as the neurotransmitter. The postganglionic fibers which are present in the parasympathetic division are cholinergic and they use acetylcholine as their neurotransmitter.