Parasympathetic Nervous System Overview

Muscarinic acetylcholine receptor

A G protein-coupled receptor that responds to acetylcholine.

Pre-ganglionic neuron

A neuron that is long in the parasympathetic nervous system.

Post-ganglionic neuron

A neuron that is short in the parasympathetic nervous system.

Parasympathetic output

Confined to the medulla and sacral region.

Sympathetic output

Confined to the thoracic and lumbar regions.

M1-3 receptors

Mainly found in glands, heart, and smooth muscle.

M4 and M5 receptors

Mainly found in the central nervous system (CNS).

Odd-numbered muscarinic receptors

Coupled to Gq proteins.

Even-numbered muscarinic receptors

Coupled to Gi proteins.

Physiological effects of sympathetic system

Fright, flight, fight.

Physiological effects of parasympathetic system

Rest and digest.