One of the two major sub-divisions of the autonomic nervous system (ANS) that conserves and restores energy in opposition to physical responses from the sympathetic nervous system. Typically promotes, for example, lower heart rate, blood vessel dilation, increased digestive secretions, and sexual arousal. Thus, it is sometimes referred to as the ‘rest and digest’ system. As with the sympathetic nervous system (SNS), the pre-ganglionic neurons and glial cells arise from the neural crest. Most of the neurons are cholinergic, with responses being mediated by muscarinic receptors. Little is known about the development of the PNS in humans. However, it is known that in preterm infants that both SNS and PNS have a markedly low level of activity during the neonatal period as measured by heart rate*. This is especially the case for the PNS relative to fullterm infants. However, by 2-3 years and beyond, activity in both branches of the ANS were indistinguishable from the fullterm group. Once again, this was particularly the case for the PNS.
Autonomic nervous system (ANS), Central nervous system (CNS), Cholinergic neurotransmitter system, Cranial nerves, Glial cells, Neural crest, Oculomotor nucleus, Peripheral nervous system, Preterm infant, Sympathetic nervous system (SNS), Vagus (or pneumogastric) nerve
* De Rogalski Landrot,I et al. (2007). Autonomic nervous system activity in premature and full-term infants from theoretical term to 7 years. Autonomic Neuroscience, 136, 105-109.