Sympathetic Division

Sympathetic Division - postganglionic fibers leave by way...

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Autonomic Nervous System Sympathetic Division * Pre and post ganglionic fibers demonstrate convergence and divergence * there is no simple one-to-one relationship between pre and post ganglionic neurons * each postganglionic cell may receive synapses from multiple preganglionic cells: neuronal convergence * each preganglionic fiber branches and synapses with multiple postganglionic fibers: neuronal divergence * allows sympathetic division to have a relatively widespread effect Sympathetic Division * Sympathetic nerve fibers leave the paravertebral ganglia by three routes: * spinal nerves * sympathetic nerves * splanchnic nerves Sympathetic Division * A. spinal nerve- postganglionic fibers exit by way of the gray ramus, return to the spinal nerve or its subdivision, and travel the rest of the way to the target organ * This is the route innervates mostly effectors in the body wall (sweat glands, piloerector muscles, and blood vessels of the skin and skeletal muscles) Sympathetic Division * C . Sympathetic nerve route-
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Unformatted text preview: postganglionic fibers leave by way of sympathetic nerves that extend to the heart, lungs, esophagus, and thoracic blood vessels * these fibers form plexus around each carotid artery and issue fibers from there to effectors in the head (sweat glands, salivary and nasal glands: piloerector muscles: blood vessels:, and dilators of the iris * Some fibers from the superior cervical ganglion form the cardiac nerves to the heart. Sympathetic Division * B. splanchnic nerve (any nerve which innervates viscera) route- formed from fibers originating predominately form T5-T12 and pass through the chain ganglia without synapsing. * beyond the ganglia, they form greater, lesser, and lumbar (least) splanchic nerves * these lead to the collateral (prevertebral ganglia which contribute to a network called the abdomino aortic plexus that wraps around the aorta * three major collateral ganglia * celiac * superior mesenteric * inferior mesenteric...
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