Parasympathetic and Visceral Sensory (AHE Block 4 Lecture 2) PDF

active during times the body must process nutrients, conserve energy, and return to homeostasis (anabolic): Parasympathetic Division Parasympathetic division axons: not components of the spinal nerves or their branches Cranial parasympathetic - Preganglionic cell bodies are located in: brainstem n...

active during times the body must process nutrients, conserve energy, and return to homeostasis (anabolic): Parasympathetic Division Parasympathetic division axons: not components of the spinal nerves or their branches Cranial parasympathetic - Preganglionic cell bodies are located in: brainstem nuclei Cranial parasympathetic - Exit via: cranial nerves Cranial parasympathetic - Synapse on: parasympathetic cranial ganglia Cranial and Sacral parasympathetic Postganglionic axons project to: target organ Parasympathetic Preganglionic axons are: long Parasympathetic Postganglionic axons are: short Cranial parasympathetic structures: Heart, Eyes, Lungs, digestive organs, Enteric NS Communication occurs between: cranial nerves nerves may begin as ______, but receive _____ fibers along its course: sensory, motor Nuclei for all CNs are in the brainstem, except: 1. CN I 2. CN II Sensory and motor communication carried within CNs will synapse on: cranial nerve nuclei in the brainstem Cranial parasympathetic - Cranial Nerves: 1. III 2. VII 3. IX 4. X CN III: Oculomotor CN VII: Facial CN IX: Glossopharyngeal CN X: Vagus Cranial parasympathetic - Postganglionic cell bodies CN III (Oculomotor): Ciliary Cranial parasympathetic - Postganglionic cell bodies CN VII (Facial): Otic Cranial parasympathetic - Postganglionic cell bodies CN IX (Glossopharyngeal): Pterygopalatine  Cranial parasympathetic - Postganglionic cell bodies CN X (Vagus): Submandibular Cranial Location of Preganglionic Associated Postganglionic Target organ Nerve nuclei in axons (exit) cranial ganglion axons brainstem (synapse) CN III Midbrain CN III Ciliary ganglion Short ciliary Ciliary muscles: nerves lens accommodation Sphincter pupillae muscles: pupil constriction CN IX Medulla CN IX Otic ganglion Travel with Parotid gland: branch of the increase saliva flow mandibular nerve (CN V3) CN X Solitary CN X Terminal or Very short intramural axons within Heart: slows heart nucleus: Travels thru ganglia located the target rate visceral sensory neck into near or within organs thorax target organs. Lungs: (monitor bronchoconstriction internal environment) Passes thru diaphragm Digestive organs: stimulates motility and secretion Dorsal nucleus: Liver and visceral pancreas: motor regulates metabolic and digestive Nucleus function. ambiguus: visceral motor to heart CN VII Pontic CN VII Nuclei: base Route A: of pons Route A: Route A: Route A: Lacrimal glands: Petrosal Pterygopalatine maxillary tear production. Nerve Ganglion nerve (CN V2) Nasal and palatal mucosa: mucus secretion Route B: Route B: Route B: Route B: Chorda Submandibular supply the Submandibular Tympani Ganglion submandibular and sublingual and sublingual glands: saliva glands. secretion 3.Recall the spinal contribution and pre and postganglionic pathway for parasympathetic sacral outflow, effects, and target organs Sacral parasympathetic - Preganglionic cell bodies are located in: spinal cord segments S2-S4 Sacral parasympathetic - Exit via: anterior roots of sacral spinal nerves, BRANCH, forming pelvic splanchnic nerves from anterior rami Sacral parasympathetic - Synapse on: target or intramural ganglia at organ Sacral parasympathetic Structures: Bladder, penis, rectum, distal large intestine Sacral pelvic splanchnic nerves: contribute to superior and inferior hypogastric plexuses (distal portion of internal organs) Sacral flow causes: 1. Increased smooth muscle motility and secretory activity in digestive tract 2. Contraction of smooth muscle in bladder wall 3. Erection of clitoris and penis Cardiac Plexus: In thoracic cavity’s mediastinum Sympathetic Contribution: ○ Origin: Postganglionic axons from sympathetic trunk, superior, middle, inferior cervical ganglion, T1-T5  ○ Pathway: Preganglionic fibers synapse in the cervical and upper thoracic sympathetic ganglia, Postganglionic fibers travel to the cardiac plexus. ○ Effect: Increases heart rate, increases BP, vasodilation Parasympathetic Contribution: ○ Origin: Preganglionic axons from nucleus ambiguus and CN X ( Vagus) ○ Pathway: Preganglionic fibers synapse in ganglia within or near the heart wall. ○ Effect: Decreases heart rate, vasoconstriction Pulmonary Plexus: surrounds bronchi & blood vessels of lungs Sympathetic Contribution: ○ Origin: Postganglionic axons from sympathetic trunk, T1-T5 ○ Pathway: Postganglionic fibers from thoracic sympathetic ganglia. ○ Effect: Bronchodilation and reduced mucus secretion. Parasympathetic Contribution: ○ Origin: Preganglionic axons from dorsal nucleus and CN X ( Vagus) ○ Pathway: Preganglionic fibers synapse in ganglia within the pulmonary plexus or lung tissue. ○ Effect: Bronchoconstriction, increased mucus secretion, vasodilation in pulmonary vessels. Esophageal Plexus: controls swallowing reflex Sympathetic Contribution: ○ None. Parasympathetic Contribution: ○ Origin: Preganglionic axons from CN X ( Vagus) ○ Effect: innervates smooth muscle in the inferior esophagus and cardiac sphincter (circular muscle/valve at opening of stomach), promotes peristalsis Abdominal Plexuses (Celiac, Superior, Inferior) - All interconnected - All parasympathetic comes from CN X (Vagus) - All activity is the same - Sympathetic: vasoconstriction - Parasympathetic: vasodilation 1. Celiac (Solar) Plexus Sympathetic Contribution: ○ Origin: Greater, lesser, least, splanchnic nerves from T5-T12  ○ Pathway: Preganglionic fibers synapse in Celiac, aorticorenal, superior mesenteric ganglia 2. Superior Mesenteric Plexus Sympathetic Contribution: ○ Origin: Least splanchnic nerves from T10-T12 ○ Pathway: Preganglionic fibers synapse in the superior mesenteric ganglion. 3. Inferior Mesenteric Plexus Sympathetic Contribution: ○ Origin: Lumbar splanchnic nerves (L1-L2 spinal segments). ○ Pathway: Preganglionic fibers synapse in the inferior mesenteric ganglion. Hypogastric Plexus: innervate viscera within pelvic region Sympathetic Contribution: ○ Origin:Postganglionic axons from Lumbar and sacral splanchnic nerves (L1-L2) ○ Pathway: Preganglionic fibers synapse in the superior hypogastric ganglia, and postganglionic fibers contribute to the inferior hypogastric plexus. ○ Effect: vasoconstriction, contraction of muscles (sphincter of bladder, anus), ejaculation, remission of erection Parasympathetic Contribution: ○ Origin: Preganglionic axons from Pelvic splanchnic nerves (S2-S4). ○ Pathway: Preganglionic fibers synapse in ganglia near the pelvic organs. ○ Effect: vasodilation, relaxation of muscles (sphincter of bladder, anus), engorgement of erectile tissue. Enteric system: ”second brain” functions independently from CNS thru reflexes, postganglionic parasympathetic motor neurons in GI tract Help maintain homeostasis: Autonomic/Visceral reflexes Visceral afferent fibers provide information about: the condition of the body’s internal environment (unconscious thought) Visceral sensation: Integrated in the CNS, triggered by visceral and/or somatic reflexes which regulate blood pressure and chemistry by altering function of target organs (e.g., heart rate) Most visceral _____ sensations travel with parasympathetic fibers (but in opposite direction): reflex Most visceral _____ impulses travel along-side with sympathetic fibers: pain Conscious ______ is usually perceived as poorly localized pain (e.g., cramps, fullness, nausea, hunger): sensation Conscious _____ is usually caused by spasms, contractions, chemical irritants, ischemia (low blood supply): pain