Autonomic Nervous System Notes PDF

Autonomic Nervous System Instructors Prof. Mohammed Al-Hariri email: [email protected] Dr. Kholoud Al-Ghamdi [email protected] Department of Physiology Learning outcomes At the end of this session, students should be able to; ➢ Understand the general anatomical arrangement of the auto...

Autonomic Nervous System Instructors Prof. Mohammed Al-Hariri email: [email protected] Dr. Kholoud Al-Ghamdi [email protected] Department of Physiology Learning outcomes At the end of this session, students should be able to; ➢ Understand the general anatomical arrangement of the autonomic nervous system (ANS) ➢ Outputs from the brain, via the spinal cord ➢ Explain central autonomic network: ➢ The main brain nuclei involved in autonomic nervous system responses ➢ The pathways from the periphery to these central nuclei ➢ Describe the main functions of the ANS ➢ Explain the sympathetic and parasympathetic divisions of the ANS ➢ Discuss how ANS can achieve such a wide range of functions ➢ Understand the role of the adrenal medulla in ANS function and our ability to survive trauma ➢ Give examples of autonomic reflex's that use central connections Wednesday, November 29, 2023 A case of Organophosphate poisoning ▪ 40-year-old semiconscious male is brought to the Ñ emergency department having deliberately ingested pesticide 4 hours previously. On examination , he has mornin fixed pinpoint pupils (miosis) , generalized paralysis, fasciculations, and is unresponsive to deep pain. Corneal and gag reflexes are absent. He has profuse salivation, sweating , and excess lacrimation. He has been incontinent of urine and feces. I I Wi NIH ▪ Vital signs include the following: blood pressure 140/90 mm Hg, temperature 99.2°F (37.2°C), pulse 58 beats/minute and regular. Rales are noted during chest auscultation. Heart sounds are normal. Abdominal examination reveals no detectable masses, organomegaly, or hyperactive bowel sounds. Wednesday, November 29, 2023 CNS processing © 2018 Pearson Education, Inc. CNS processing © 2018 Pearson Education, Inc. CNS processing © 2018 Pearson CNS processing © 2018 Pearson CNS processing twist 0 Defendingpathway AS © 2018 Pearson Education, Inc. 1 SympatheticFight orFlight Heart rate, blood pressure, and respiration increase Adrenal medulla secretes epinephrine and norepinephrine EE Parasympatherti III we n sympathetic IT aim TfiI Blood flow to Stomach skeletal muscles contractions increases are inhibited Efftition Wednesday, November 29, 2023 Wednesday, November 29, 2023 The Autonomic Nervous System Decsending The autonomic nervous system(ANS) is that part of our nervous system which controls all the vital functions and other physiological processes which mostly do not come under voluntary control. IFAutonomic Means As the word autonomy indicates it is a self regulating part of the nervous system. ANS part of ourNervous processesWhich system Mostly Do not Autonomy which controls come under all vitalFunction otherphysiological voluntary control Melicate selfregulation part of NS f pretff.IT ytp.se autonomic 0 t.I.me somatic Ii • Autonomic nervous system – Chain of G two motor neurons • Preganglionic neuron • Postganglionic neuron of – Conduction is slower due to thinly or unmyelinated axons i i Éfg Éf tf.ws onmytgtdcondu 000 gang postganglionic Autonomic Nerve pathways ▪ The pathway is from the CNS to the effector organ ▪ The pathways consists of a two neuron chain: 1. The cell body of the 1st neuron lies in the CNS The cell body of the 2nd neuron lies in a ganglion Implemented A GANGLION: 2. outside CN A group of neuronal cell bodies located outside the CNS ofneuroalanbodyloatdouts.IO CNS ans Ganglion Locatedoutside CNS Group of Neuronal CellBody #1 #2 0 Preganglionic F Lies If to Effector organ Postganglionic F D ber ganglion Wednesday, November 29, 2023 wait plighglionic Brain is ACh long Spinal cord ACh short ym organs É Terminal ganglion I = Preganglionic fiber = Postganglionic fiber NE Effectorgon aforepreti g parasympathetic Smooth muscle Thoracolumbar sympathetic nerves Titty Adrenal medulla atony = Acetylcholine = Norepinephrine = Epinephrine = Cell body = Cell body = Axon sympatutin Blood E,NE NE ACh Collateral ganglion ACh sacral = Parasympathetic system Cardiac muscle Sympathetic ganglion chain Craniosacral parasympathetic nerves = Sympathetic system ACh Effector Terminal ganglion Most exocrine glands and some endocrine ACh glands Location of Preganglionic Cell Bodies Sympathetic Thoracolumbar T1 – L2/L3 levels of the spinal cord Parasympathetic Craniosacral 74720 3 7 9 1 Brain: CN III, VII, IX, X Spinal cord: S2 – S4 z 54 Wednesday, November 29, 2023 Not Autonomic Directfs noganglia o Ganglia Topreganglionic is tall post99f in para Faine E Autonomic nervous system discharge Sympathetic Parasympathetic Dominates in stressful condition Dominates in quiet, relaxed condition I 2 Generalized effect Fight-to-flight response a Localized effect Involves discrete organs E.g.,defecation & micturition Autonomic nervous system Sympathetic Parasympathetic  Heart rate & force of contraction i µg of bronchioles dilation 0  Blood pressure  Metabolism glucose & fatty acids  Heart rate constriction of bronchioles  Blood pressure em is If I I Autonomic nervous system Sympathetic Dilate pupil Far vision Ifta 11155  sweating g at El su Parasympathetic f Constrict pupil Near vision Usually both subdivisions are active in controlling the activity of an internal organ This ongoing activity is called sympathetic or parasympathetic Tone Activity The Balance between that happens on Wednesday, November 29, 2023 two www.ww The visceral organs receive Dual Innervation They are signaled by both subdivisions of the ANS There are some Exceptions … Wednesday, November 29, 2023 1. Sweat Glands she Mai saw Most sweat glands are innervated only by e Sympathetic nerves But postganglionic fibers secretes Acetyl choline For epinephrine 2. Salivary Glands Fay Both Sympathetic and Parasympathetic subdivisions stimulate the activity of salivary glands but the saliva’s a. Volume b. Composition me differ depending on which autonomic branch is dominant. Parotid Gland Submadibular Gland Sublingual Gland 3-Blood vessels Blood vessels receive mainly sympathetic innervation If a1 is stimulated µ Vasoconstriction If b2 is stimulated Vasodilation Post ganglionic fibers to the blood vessels of skeletal muscles release acetylcholine Vasodilation Wednesday, November 29, 2023 Metabolic effects of Sympathetic stimulation e I Presentation title Wednesday, November 29, 2023 II- Adrenergic receptors {Receptors for Adrenaline & Noradrenaline} vasoconstriction ftp.ffugg _tasodilation Bronelodi Adrenal gland is exception On top of kidneys Adrenal medulla (inside part) is a major organ of the sympathetic nervous system Wednesday, November 29, 2023 Adrenal gland is exception ▪ Synapse in gland ▪ Can cause body-wide release of epinephrine (aka adrenaline) and norepinephrine in an extreme emergency (adrenaline “rush” or surge) Eighteen Wednesday, November 29, 2023 Spinal cord = Acetylcholine (A.Ch) I = Norepinephrine ( NE ) Sympathetic preganglionic fiber = Epinephrine ( E ) Adrenal medulla A.Ch NE , E Sympathetic postganglionic fiber Blood NE Target organs Summary Wednesday, November 29, 2023 e Each Autonomic Neurotransmitter binds to several different Receptors Neurotransmitters in the ANS Acetylcholine (Ach) Norepinephrine (NE)/noradrenaline Released from cholinergic fibers Released from adrenergic fibers All preganglionic fibers All postganglionic parasym fibers Few postganglionic sym fibers gate Quickly inactivated Short & local effect Most postganglionic sym fibers Slowly inactivated Long & widespread effect Sites of release of Ach and NE Acetylcholine All preganglionic terminals of the autonomic nervous system All parasympathetic postganglionic Norepinephrine Most sympathetic postganglionic terminals I Adrenal medulla terminals Central nervous system Sympathetic postganglionic sympout terminals at sweat glands and some blood vessels in skeletal muscle Terminals of efferent neurons supplying skeletal muscle (motor neurons) Central nervous system Presentation title A case of Organophosphate poisoning ▪ 40-year-old semiconscious male is brought to the emergency department having deliberately ingested pesticide 4 hours previously. On examination , he has fixed pinpoint pupils (miosis) , generalized paralysis, fasciculations, and is unresponsive to deep pain. Corneal and gag reflexes are absent. He has profuse salivation, sweating , and excess lacrimation. He has been incontinent of urine and feces. ▪ Vital signs include the following: blood pressure 140/90 mm Hg, temperature 99.2°F (37.2°C), pulse 58 beats/minute and regular. Rales are noted during chest auscultation. Heart sounds are normal. Abdominal examination reveals no detectable masses, organomegaly, or hyperactive bowel sounds. Wednesday, November 29, 2023 Organophosphate (OP) poisoning ▪ OP compounds are used as commercial insecticides and applied as aerosols or dusts. ▪ They can be rapidly absorbed through skin and mucous membranes or by inhalation. ▪ These agents inhibit the enzyme acetylcholinesterase, which is responsible for the degradation of acetylcholine. ▪ Signs and Symptoms – Muscarinic signs: salivation, lacrimation, urination, diaphoresis, gastrointestinal upset, emesis and progressing to bronchospasm, bronchorrhea, blurred vision, bradycardia or tachycardia, hypotension, confusion, and shock. – Nicotinic effects: Skeletal muscle initially exhibits fasciculation (involuntary irregular, violent muscle contractions) followed by the inability to repolarize cell membranes resulting in weakness and paralysis. Severe reactions can lead to ventilatory failure and death (cholinergic crisis). ▪ Treatment – Remove clothing and wash skin with soap and water – Airway management (secretions are the main issue) – Atropine (titrated to dried secretions, not HR) Wednesday, November 29, 2023 ▪ Human Physiology: From Cells to Systems. Lauralee Sherwood Brooks Cole. ISBN-10: 0534395015. Latest edition ▪ Ganong’s Review of Medical Physiology, Latest edition ▪ Textbook of Medical Physiology, Guyton and Hall. ISBN: 978-1-4160-4574-8. Latest Edition ▪ Visual Anatomy & Physiology, 3rd edition Pearson Pain and Temperature Sensations Wednesday, November 29, 2023