Autonomic Nervous System Overview Quiz

Autonomic Nervous System Overview

• The sympathetic division of the autonomic nervous system (ANS) is responsible for innervating the heart and lungs, with specific axons from T1-T4, T5-T9, T10-T11, T12, and L1-L2 forming different splanchnic nerves.
• Paravertebral ganglia extend in chains from the base of the skull to the ganglion impar on the anterior aspect of the coccyx, with cervical, thoracic, lumbar, and sacral regions of ganglia.
• The sympathetic nervous system has a short preganglionic component and a long postganglionic component, with the axons traveling from the lateral horn in the spinal cord to the prevertebral ganglia synapse being short, and those traveling from the prevertebral ganglia to the visceral organs being long.
• Visceral structures in the head receive sympathetic innervation from cell bodies in thoracic levels, which send their axons to the cervical ganglion and then travel as the carotid plexus around the Internal Carotid Artery.
• The parasympathetic division, known as the craniosacral division, has a long pre-ganglionic component and a short post-ganglionic component, with pre-ganglionic cell bodies located in brainstem nuclei of cranial nerves III, VII, IX, X, and in cell bodies of S2-S4 in the spinal cord.
• Each cranial nerve carrying parasympathetic axons has an associated ganglion, with the Vagus nerve supplying visceral organs in the head and traveling as far caudally as the left colic flexure of the large intestine.
• Pre-ganglionic parasympathetic axons that form Pelvic Splanchnic nerves leave the ventral root before the spinal nerve is formed, and there are no parasympathetic fibers in any spinal nerve.
• The enteric nervous system, the intrinsic nervous system of the gastrointestinal tract, contains two neural plexuses: the Submucosal (Meissner’s) Plexus, which regulates GI blood flow and epithelial function, and the Myenteric (Auerbach’s) Plexus, which aids in motility, contraction, and relaxation of smooth muscle.