Question

True/False - The parasympathetic division is typically an inhibitory system while the sympathetic division is an excitatory one.

Summarize the differences between the sympathetic and the parasympathetic nervous systems with regards to these factors:

Neurotransmitters, length of fibers, receptors

Answer 1

True.Parasympathetic system acts like an inhibitory system ; while sympathetic system acts like an excitatory system.

Neurotransmitter-

In sympathetic system; it is mostly adrenaline by postganglionic fibers and acetylcholine by preganglionic fibers.The exceptions are sweat glands(acetylcholine); nor adrenaline from adrenal medulla and even dopamine.

In parasymapthetic system; it is acetylcholine by both preganglionic and post ganglionic fibers.

Length of fibers-

Preganglionic fibers are shorter in sympathetic system.

Postganglionic fibers are shorter in parasympathetic system.

Receptors-

In sympatheric system; alpha (1 and 2) and beta (1;2;3) receptors.

In parasympathetic system; muscarinic(M1;M2;M3;M4;M5) and nicotinic(Nm; Nn).