ANS III- Parasympathetic Nervous System and Visceral Sensory

ANS III- Parasympathetic and Visceral Sensory Course Learning Objective Nervous: Describe how the body communicates with itself by identifying anatomical structures and tracing pathways of the nervous system in order to aid in medical diagnoses when these s...

ANS III- Parasympathetic and Visceral Sensory Course Learning Objective Nervous: Describe how the body communicates with itself by identifying anatomical structures and tracing pathways of the nervous system in order to aid in medical diagnoses when these systems are compromised  LO 6 Lecture Learning Objectives 1. Compare and contract cranial and sacral 5. Briefly describe what the enteric nervous parasympathetic pathways including system is and what makes the enteric nervous 1. Associated CNS structures system unique 2. Associated PNS structures/ganglia 6. Explain the role and stimuli of autonomic 2. Diagram the parasympathetic pathways for CN reflexes III, VII, IX, and X including the following: 7. Explain to a friend the following regarding a. Location of nuclei in brainstem visceral sensation: b. Preganglionic axons a. Its role c. Associated cranial ganglion b. How it is stimulated d. Postganglionic axons c. Contrast the type of sensation that travels with e. Target organ sympathetic versus parasympathetic fibers d. The type and origin of visceral pain 3. Recall the spinal contribution and pre and postganglionic pathway for parasympathetic 8. Identify indicated parasympathetic terms on sacral outflow, effects, and target organs histology slide 4. List the sympathetic and parasympathetic 9. Identify the terms indicated by on supplied contributions and resulting effects for each images autonomic plexus; link these to the origins of each contribution (e.g., brainstem/spinal contributions, splanchnic or cranial nerve, type and location of ganglia) Parasympathetic Introduction  LO 1 Parasympathetic Division Most active during times the body must process nutrients, conserve energy, and return to homeostasis (anabolic) Anatomically more restricted than the sympathetic division Axons are not components of the spinal nerves or their branches Gray’s Basic Anatomy, Drake et al., 2018  LO 1 Parasympathetic Division Cranial parasympathetic outflow Preganglionic cell bodies located in brainstem nuclei Exit via cranial nerves Synapse on parasympathetic crania ganglia postganglionic axons to target organ Sacral parasympathetic outflow Preganglionic cell bodies located in spinal cord segments S2-S4 Exit via anterior roots of sacral spinal nerves forming pelvic splanchnic nerves from anterior rami Synapse on ganglia in (intramural) or near (terminal ganglia) target organ postganglionic organs to target organ Preganglionic axons are long and postganglionic axons are short Clinically Oriented Anatomy, Moore et al., 2018 Cranial Outflow  LO 2 Cranial Nerves: Introduction 12 pairs Numerically ordered using roman numerals Which motor pathway travels through cranial nerves? How is sensory information from head and neck transmitted? Sensory and motor communication carried within CNs will synapse on cranial nerve nuclei Nuclei for all CN are in brainstem, except CN I and II Travel through openings in crania and are covered with protective CT continuous with meninges Communication occurs between cranial nerves E.g., nerves may begin as sensory, but receive motor fibers along its course Cranial Nerves and Nuclei CN III CN VII CN IX CN X  1 LO 2 2 Cranial Outflow 3 Preganglionic cell bodies in cranial nerve nuclei in brainstem Cranial nerves III (Oculomotor) VII (Facial) IX (Glossopharyngeal) X (Vagus) Postganglionic cell bodies in parasympathetic cranial ganglia 1. Ciliary 2. Otic 3. Pterygopalatine 4. Submandibular 4 Postganglionic axons Target organ/muscle  Mesencephalic nuclei Ciliary ganglion LO 2 Cranial Outflow- CN III Exits brain stem near midline at superior aspect of pons Cranial nerve III (Oculomotor) Preganglionic cell bodies in mesencephalic nuclei Exit via CN III CN III Synapse in ciliary ganglion Postganglionic fibers to 1. Ciliary muscles 2. Sphincter pupillae muscles of iris and eye Lens accommodation and pupillary constriction  LO 2 Cranial Outflow- CN VII Pterygopalatine Cranial nerve VII (Facial) ganglion Preganglionic cell bodies in pontic Greater Pontic nuclei nuclei petrosal Exit via CN VII nerve A Greater petrosal nerve Synapse on pterygopalatine ganglion Lacrimal gland and smaller glands of nasal and oral cavity Tear production, nasal secretion B Chorda Chorda tympani tympani Synapse on submandibular ganglion Submandibular and sublingual glands Submandibular Saliva production ganglion  Otic ganglion LO 2 Cranial Outflow- CN IX Medullary nuclei Cranial nerve IX (Glossopharyngeal) Preganglionic cell bodies are house in medullary nuclei Exit via CN IX Synapse on otic ganglion postganglionic fibers to parotid gland Increased saliva flow Parotid gland  LO 2 Cranial Outflow- CN X Cranial nerve X (vagus= wanderer) ~80% of all parasympathetic innervation comes from CN X Supplies parasympathetic innervation to the thoracic and abdominal cavities Thoracic Heart Respiratory tract (larynx to lungs) Abdomen Liver, gallbladder, pancreas Kidneys Digestive tract from esophagus down to proximal half of large intestines Gonads (testes and ovaries) Clinically Oriented Anatomy, Moore et al., 2018  LO 2 Cranial Outflow- CN X Cranial nerve X (vagus= wanderer) Preganglionic cell bodies are house in medullary nuclei a. Solitary nucleus- visceral sensory b. Dorsal nucleus- visceral motor c. Nucleus ambiguus- visceral motor to heart d. (Spinal trigeminal nucleus) Exit via CN X Travels through neck into thorax Branches into anterior and posterior vagal trunks Synapse on terminal or intramural ganglia Target organ Thoracic cavity: increased mucous production, decreased diameter of airways, decreased heart rate and contraction force Passes through diaphragm Abdominal cavity: increases smooth muscle motility and secretory activity in digestive organs(increased digestion) Sacral Outflow  LO 3 Sacral Outflow Preganglionic cell bodies in spinal cord levels S2-S4 Leave via anterior root Branch to form pelvic splanchnic nerves Contribute to superior and inferior hypogastric plexuses Synapse in target or intramural ganglia (location of postganglionic cell bodies) at organs Clinically Oriented Anatomy, Moore et al., 2018  LO 3 Sacral Outflow Innervates distal portion of large intestines, rectum, most reproductive organs, urinary bladder, distal ureter Increased smooth muscle motility and secretory activity in digestive tract Contraction of smooth muscle in bladder wall Erection of clitoris and penis  LO 3 Sacral Outflow Female pelvis: Anterior View Innervates distal portion of large intestines, rectum, most reproductive organs, urinary bladder, distal ureter S2 Increased smooth muscle S3 S4 motility and secretory activity in digestive tract Contraction of smooth muscle in bladder wall Erection of clitoris and penis Female pelvis: Lateral View Autonomic Plexuses  LO 4 Autonomic Para Sym Plexuses Collection of Pulmonary postganglionic sympathetic fibers + plexus Cardiac plexus preganglionic parasympathetic fibers + visceral sensory Esophageal Axons travel next to one another, but plexus do not interact Abdominal plexus Cardiac plexus Organ Pulmonary plexus Esophageal plexus Abdominal plexus Celiac plexus Superior mesenteric plexus Inferior mesenteric plexus Hypogastric plexus Hypogastric plexus  LO 4 Cardiac Plexus In thoracic cavity’s mediastinum Postganglionic sympathetic axons from sympathetic trunk: superior, middle and inferior cervical ganglion, T1-T5 Preganglionic parasympathetic axons from nucleus ambiguus and vagus nerve/CN X Sympathetic activity- increased heart rate and blood pressure, vasodilation Parasympathetic activity- decreased heart rate, vasoconstriction Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Pulmonary Plexuses Surrounds bronchi and blood vessels of the lungs T T Postganglionic sympathetic axons from sympathetic trunk- T1-T5 Preganglionic parasympathetic axons from dorsal nucleus and vagus nerve/CN X Sympathetic activity- bronchodilation (increased diameter of bronchi) Parasympathetic activity- bronchoconstriction (decreased diameter of bronchi) and increased secretion from mucous glands Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Esophageal Plexuses Controls swallowing reflex No sympathetic activity E Preganglionic parasympathetic axons from vagus nerve/CN X Parasympathetic activity- Stomach innervates smooth muscle in the inferior esophagus and cardiac sphincter (circular muscle/valve at opening of stomach), promotes peristalsis Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Abdominal Plexuses Named for vessels they surround Includes celiac, superior and inferior mesenteric plexuses (aortic plexus) Postganglionic sympathetic axons from prevertebral ganglia Preganglionic parasympathetic axons from vagus nerve/CN X Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Abdominal Plexuses All are interconnected All parasympathetic comes from vagus nerves 1. Celiac plexus Sym- Greater, lesser and least splanchnic nerves Celiac, aorticorenal, superior mesenteric ganglia 2. Superior mesenteric plexus Sym- Least splanchnic nerves Superior mesenteric ganglia 3. Inferior mesenteric plexus Sym- lumbar splanchnic nerve Inferior mesenteric ganglia Sympathetic activity- vasoconstriction Parasympathetic activity- vasodilation Gray’s Basic Anatomy, Drake et al., 2018  LO 6 LO 4 Hypogastric Plexuses Innervate viscera within pelvic region Postganglionic sympathetic axons from lumbar and sacral splanchnic nerves Preganglionic parasympathetic axons from pelvic splanchnic nerve Sympathetic activity- vasoconstriction, contraction of muscles (sphincter of bladder, anus), ejaculation, remission of erection Parasympathetic activity- vasodilation, relaxation of muscles (sphincter of bladder, anus), engorgement of erectile tissue Gray’s Basic Anatomy, Drake et al., 2018  LO 5 Enteric System Postganglionic parasympathetic motor neurons of the GI tract More function than just receiving and passing on input from preganglionic fibers “Second brain”- “due to its complexity, integrative function, and ability to function autonomously, without connection to the CNS” Gray’s Basic Anatomy, Drake et al., 2018 Plexus Sympathetic (thoracolumbar) Input Parasympathetic Result LO 4 (craniosacral) Input Cardiac Spinal levels: Brainstem level/nuclei: S: __________ heart rate and strength of contraction Sympathetic trunk ganglia: Cranial nerve: CN __ P: ___________ heart rate and strength of contraction Splanchnic nerve: Pulmonary Spinal levels: Brainstem level/nuclei: S: Broncho_________, decrease secretions Sympathetic trunk: Cranial nerve: CN __ P: Broncho___________, increase secretion Splanchnic nerve: Esophageal None Brainstem level/nuclei: S: None P: Control of stomach sphincter, Cranial nerve: CN __ Plexus Sympathetic (thoracolumbar) Input Parasympathetic (craniosacral) Result LO 4 Input Abdominal Spinal levels: T5-L2 Brainstem level/nuclei: S: Primarily vaso____________ _____________ digestive (solitary nucleus receives visceral afferent secretions form organs) Cranial nerve: CN __ P: Primairly vaso_____________, _____________ digestive secretions Celiac plexus ___________ splanchnic - celiac ganglia _______ splanchnic- aorticorenal ganglia _______ splanchnic- superior mesenteric ganglia Superior mesenteric plexus _______ splanchnic- superior mesenteric ganglia Inferior mesenteric plexus _______ splanchnic- inferior mesenteric ganglia Plexus Sympathetic (thoracolumbar) Input Parasympathetic (craniosacral) Result LO 4 Input Hypogastric Spinal levels: L1- L2 Spinal levels: S: Urinary: Superior and Splanchnic nerve and prevertebral ganglion: inferior _________ splanchnic nerve- _________ Digestive: _____________ ganglion Splanchnic nerve: P______ splanchnic nerve Sacral splanchnic nerve External genitalia: P: Urinary: Digestive: External genitalia: Autonomic Reflexes  LO 6 Autonomic or Visceral Reflexes Helps maintain homeostasis Smooth muscle contractions, cardiac muscle contractions, secretions by glands that are responses to specific stimuli Information about distension, blood gas, blood pressure levels from hollow organs or blood vessels E.g., Respiratory movement of the diaphragm is controlled mostly by reflexes stimulated by levels of oxygen and carbon dioxide in blood Clinically Oriented Anatomy, Moore et al., 2018 Visceral Sensation  LO 7 Visceral Sensation Visceral afferent fibers provide information With local anesthesia, visceral organs about the condition of the body’s internal can by handles, cut, clamped, or environment cauterized without causing pain Mostly unconscious Conscious sensation is usually perceived as poorly localized pain (e.g., cramps, Integrated in the CNS, triggered by visceral fullness, nausea, hunger) and/or somatic reflexes which regulate blood pressure and chemistry by altering Pain may be caused by function of target organs (e.g., heart rate) Sudden distension Spasms or strong contractions Most visceral reflex sensations travel with Chemical irritants parasympathetic fibers (but in opposite Mechanical stimulation (when organ is direction) active) Pathological conditions, especially those Most visceral pain impulses travel along-side causing ischemia (inadequate blood supply) with sympathetic fibers Why is this important? Parasympathetic Histology  LO 8 Histology- Parasympathetic Parasympathetic ganglia Neurons Parasympathetic Intramural LO 8 Ganglia Histology a. Intramural parasympathetic ganglion b. Neuron cell bodies c. Satellite cells Gray’s Basic Anatomy, Drake et al., 2018 Vagus Nerve LO 9  LO 9 1 Abdominal Plexuses 2 1. Celiac plexus and ganglia 3 2. Superior mesenteric plexus and ganglia 3. Inferior mesenteric plexuses and ganglia  LO 9 Hypogastric Plexuses 1. Superior hypogastric plexus 2. Inferior hypogastric plexus 1 2