Postganglionic autonomic fibers refer to the nerve fibers that transmit signals from the autonomic ganglia to the target organs or tissues. They are the second part of a two-neuron system within the autonomic nervous system (ANS). The ANS is responsible for regulating and controlling involuntary bodily functions such as heart rate, digestion, and breathing.
After receiving information from the preganglionic fibers, which extend from the central nervous system (CNS) to the ganglia, postganglionic fibers relay the signals to their respective target areas. These fibers are classified based on the specific division of the ANS to which they belong: the sympathetic division or the parasympathetic division.
In the sympathetic division, postganglionic fibers release norepinephrine as their primary neurotransmitter, except for the fibers that innervate sweat glands, which use acetylcholine. These fibers help initiate the "fight-or-flight" response, preparing the body for intense physical activity and stress.
In the parasympathetic division, postganglionic fibers release acetylcholine as their neurotransmitter. This division is generally responsible for promoting rest, relaxation, and digestion.
Overall, postganglionic autonomic fibers play a crucial role in transmitting signals from the autonomic ganglia to the target organs or tissues, allowing for the precise regulation and control of involuntary bodily functions.
