Autonomic Nervous System Parasympathetic PDF

The Autonomic Nervous System: Parasympathetic Nervous System Dr Jane Jackson [email protected] Where opportunity creates success XY2141 -Physiology  Autonomic nervous system...

The Autonomic Nervous System: Parasympathetic Nervous System Dr Jane Jackson [email protected] Where opportunity creates success XY2141 -Physiology  Autonomic nervous system Nervous System Central Nervous System Peripheral Nervous System Sensory nervous Motor nervous Brain Spinal Cord system system Autonomic nervous Involuntary system Voluntary nervous system responses - homeostasis Parasympathetic Sympathetic nervous nervous system system Fight, flight, fright rest and digest Autonomic nervous system  Sympathetic nervous system: Overview© Sympathetic Pre-ganglionic chain ganglia neurones exit Exit via ventral root © Guyton and Hall 2021 https://www.clinicalkey.com/student/content/toc/3-s2.0-C20170004883 Adrenergic Receptors on SNS Phospholipase C  Autonomic nervous system Vagus nerve © Guyton and Hall 2021 https://www.clinicalkey.com/student/content/toc/3-s2.0-C20170004883  Autonomic nervous system © Guyton and Hall 2021 https://www.clinicalkey.com/student/content/toc/3-s2.0-C20170004883 Cholinergic Receptors in the ANS Nicotinic receptors on post ganglionic neurons Two types N1 and N2 also known as NM and NG. N1 found on motor end plates of skeletal muscle postganglionic neurons N2 (both Sympathetic and Parasympathetic) Ionotropic causing Na+/Ca2+ influx Muscarinic receptors on effector organs M1, M2 & M3 are main sub-types Found on cell surface of effector organs eg smooth muscle, glands or cardiac muscle (M2). metabotropic M1 & M3 are excitatory, M2 inhibitory Physiology, Cholinergic Receptors - StatPearls - NCBI Bookshelf (nih.gov) Drugs affecting Cholinergic Receptors Different drugs/ chemicals affect receptors affecting their mechanisms Atropine Pilocarpine Methacholine Muscarine Hexamethonimum Decamethonium Scopolamine Drugs affecting nicotinic receptors affect the opening of ion channels Drugs affecting muscarinic receptors affect the activity of adenyl cyclase Overall effects of sympathetic and parasympathetic systems Rest/digest Fight/ Flight Is Stress Always a Bad Thing? — Doctor Yogi (doctor-yogi.com) Doctoryogi.com 2022  Autonomic CNS Centres Medulla Cardiovascular and respiratory control. Hypothalamus: Contains vagal nuclei. Integrates sensory input, circadian cues. Excitatory/inhibitory projections. Pons Midbrain: Pupillary control. Fight or Regulates respiration. Contains flight responses. cranial nerve nuclei. Some organs are not affected by the Parasympathetic system Organs/ structures without parasympathetic innervation Adrenal medulla Pilomotor muscles (hair erector) Sweat glands Spleen Many blood vessels Heart Rate control: an Example of Dual Innervation Relative activation influences net physiological response Some organs are not affected by the Parasympathetic system Organs/ structures without parasympathetic innervation Adrenal medulla Pilomotor muscles (hair erector) Sweat glands Spleen Many blood vessels Some structures are only affected by the Parasympathetic system Organs/ structures solely parasympathetic Ciliary muscles –focusing of the eye Constrictor pupillae muscles of the iris Pupillary Reflex Dilation Constriction  SYMPATHETIC VS PARASYMPATHETIC TONE Overview -Sympathetic - baseline activation prepares for stress response -Parasympathetic - activated during rest to promote digestion, recovery -Balance determines net autonomic effect on organ function THANK YOU