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Autonomic Nervous System - Anatomy & Physiology (view source)
Revision as of 14:58, 9 March 2011
, 14:58, 9 March 2011→Parasympathetic Nervous System
==Parasympathetic Nervous System==
==Parasympathetic Nervous System==
The PNS is only activated during rest and can be used to regulate systems during functions such as digestion. Preganglionic parasympathetic neurons have cell bodies that are located in two seperate parts of the CNS, rather than running almost the full length of the CNS as the SNS does. The PNS has preganglionic neurons located in the brain stem and the sacral part of the spinal cord. Four of the cranial nerves supply parasympathetic innervation to the majority of the bodies glands and internal organs. In particular the vagus nerve (tenth cranial nerve) is responsible for a major proportion of PNS innervation. The PNS fibres located within the lateral horns of 2 or 3 sacral segments are responsible for innervation of the sex organs, urinary bladder and the rectum. PNS ganglia are located either adjacent to or within thwe wall of target organs and in contrast to SNS ganglia, there are no interconnections between ganglia in the PNS.
The PNS is only activated during rest and can be used to regulate systems during functions such as digestion. Preganglionic parasympathetic neurons have cell bodies that are located in two seperate parts of the CNS, rather than running almost the full length of the CNS as the SNS does. The PNS has preganglionic neurons located in the brain stem and the sacral part of the spinal cord. Four of the cranial nerves supply parasympathetic innervation to the majority of the bodies glands and internal organs. In particular the vagus nerve (tenth cranial nerve) is responsible for a major proportion of PNS innervation. The PNS fibres located within the lateral horns of 2 or 3 sacral segments are responsible for innervation of the sex organs, urinary bladder and the rectum. PNS ganglia are located either adjacent to or within thwe wall of target organs and in contrast to SNS ganglia, there are no interconnections between ganglia in the PNS.
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Postganglionic parasympathetic neurons that lead to the digestive tract differ from other organ connections with the PNS as within the GI tract they become part of a plexus of neurons within the walls of the tract. This complex network of neurons is referred to as the ''enteric nervous system'' (ENS). The ENS includes sensory and motor components and is therefore of vital importance in regulating smooth muscle within the GI tract.
[[Category:Nervous System - Anatomy & Physiology]]
[[Category:Nervous System - Anatomy & Physiology]]
[[Category:To Do - A&P]]
[[Category:To Do - A&P]]