7.2.1 The parasympathetic nervous system
Figure 7.7 Parasympathetic nervous system (Copyright QUT, Sheila Doggrell)
There are at least 3 types of functional muscarinic receptors in the periphery: M1- (which are found in the stomach), and muscarinic M2- and M3-receptors (which are found on other end organs and glands).
The parasympathetic nerves emerge from the cranio-sacral region of the spinal cord, and have long pre-ganglionic fibres that release acetylcholine on to NN receptors at the ganglia (Figure 14.1). The short post-ganglionic fibre also releases acetylcholine, but this time on to muscarinic receptors.
