Figure 3.

Autonomic parasympathetic input from the dorsal motor nucleus of the vagus nerve connecting the CNS with the ENS. The cartoon summarizes the main types of ENS neurons, including intrinsic primary afferent neurons (IPANs), ascending (orally directed) and descending (anally directed) interneurons, secretomotor neurons, and inhibitory and excitatory motor neurons. IPANs, which are located in the submucosal and myenteric plexuses, project both orally and anally to make synapses with all ENS cell types.