Autonomic Nervous System PDF

AUTONOMIC NERVOUS SYSTEM  Autonomic nervous system Division of the Autonomic Nervous System 1- Sympathetic Nervous System Arises from the lateral horn of all thoracic segments + upper 2 lumbar other of segments. sympathetic name (thoraco...

AUTONOMIC NERVOUS SYSTEM  Autonomic nervous system Division of the Autonomic Nervous System 1- Sympathetic Nervous System Arises from the lateral horn of all thoracic segments + upper 2 lumbar other of segments. sympathetic name (thoraco-lumbar outflow( i  2) Parasympathetic Nervous System Arises from 2 Origins: - Cranial part: From cranial nerves III, VII, IX and X. 7 11 - Second part: From 2, 3 and 4th lateral horn of sacral segments of spinal cord. (craniosacral outflow)  Autonomic Ganglia outside any neurons is the site of contact between CNS Wecallit Gangl preganglionic and postganglionic Efferent neurons.  Types of autonomic ganglia 1: Lateral (Sympathetic chain) inthesympathatic 2: Co-Lateral ganglia SupMesenteric pterygopalatine ganglion Mesenteric Ifa Ciliaryganglion Submandibularganglion 3. Terminal ganglia  Functions of autonomic Ganglia 1- Relay stations: at which the function of ANS can be Control 2- Distributing center: each preganglionic nerve fiber relay with 8-9 postganglionic neurons.  Site of the ganglia 1. Sympathetic ganglia mostly in A) Sympathetic chain (Lateral ganglia) B) Or in co-lateral ganglia ( celiac, superior and inferior mesenteric ganglia) 2. Parasympathetic ganglia: usually terminal ganglia (inside the organ) or very near to the organ Functions of Sympathetic Nervous System  for fisht alwaysgeneralizedeffect 2 Sweating catabolic 3 4 5 6 7 medulla Adrenal 8 secrete 80 hate 20 odvesselsof skin 10 contraction of the 9 constriction Capsulearound spleen advesselsofBrain becauseitcontain300m Blood dilation  Functions Of Parasympathetic Nervous System anabolic Rest pupilconstriction Localizedeffect organsdoesn'thave parasympathetic Sypply 1 Spleen 2AdrenalMedulla 3 Ventricles 4 Bloodvesselstoskin 5 1111 ToSkeletalMuscle Comparison between sympathetic and parasympathetic actions  Supra-spinal control of the Autonomic For Nervous system sympathetic 1. Posterior and anterior Hypothalamic nuclei storparasympathic 2. Medullary centers for Autonomic functions (as CVS and RS). ** Organs under autonomic control usually receive double nerve supply; Parasympathetic and sympathetic. During rest, One of them has the upper hand Chemical Transmitters Adrenalin notneurotransmitter in autonomic Types: Adrenalin secreted as Hormone Adrenalin Neurotransmitter in inblood brain 1) Acetylcholine (Ach): secreted at the end of cholinergic neurons 2) Nor-adrenaline (NA): secreted at the end of adrenergic neurons. Acetylcholine (Ach) ganglionicsympathetic pre pre ganglionic parasympathetic postganglionic parasympathetic postsympatheticBloodvesselsofskeletalm andsweat glands Release Ach postgangiolic Sympathatic Release NA  Drugs oh Ganglion Stimulant: Nicotine small dose Jeff Ganglion Blocker: Nicotine Large dose Drugs affecting parasympathetic nervous system: aiw. o 1. Parasympathomimetic Drugs a. Acetylecholine and methacholine b. Muscarinic Drugs: Drugs stimulate the peripheral cholinergic receptors (at the effector so organs) e.g. Muscarine. II. Parasympatholytic Drugs (Ach. Antagonists) They act by: * Blocking muscarinic-like actions of Ach e.g. atropine J1 w̅ parasympathetic notnicotinic AtropinJI L II 1Beforeoperations 2Diliationsofthepupil 3 Forabdominalpain wit 4 patientswhoare exposed to organophosphatcompound  NORADRENALINE * Formation: from amino acid phenylalanine. * Site of Release: * Postganglionic Sympathetic fibres EXCEPT ???. Post Blood ofskeletalM adrenal MedullaandSweatglands sympathetic vessels * Adrenergic Receptors - Adrenergic receptors are present in the effector organs. Vasoconstriction Vasodiliation They are classified into alpha (alpha O 1 & alphaO 2, Alpha 3) and beta (beta O 1 & beta O 2) adrenergic receptors. forHeart lung Bronche Relaxing contraction  Adrenergic Receptors JII gt.LI II. Sympathomemtic drugs Bhagya As Beta 1 & 2 receptor's stimulants e.g. Isoprenaline. hotspecificheauseitwork on B1 and B2 in icu emergency  Sympal lic a II. Sympatholytic drugs it so * Alpha blockers : block α-1 I s receptors e.g. Phentolamine β-1Ifreceptors Blocker e.g. Atenolol Tomanagehypettens (antihypertensive drug) Selective 3 19 * Beta 1 and 2 blockers : e.g. Propranolol (Indral) Non Selective B1 B2 Jlt  Special features of autonomic nerves function 1. Control of the level of activity of the viscera 2. Have a basal level of discharge 3. The effect of sympathetic stimulation is usually generalized While that of the parasympathetic is usually localized  Non-adrenergic Non-cholinergic autonomic neurons a. Found in the intrinsic nerves of the gut (Enteric nervous system) a. Release peptides transmitters Too (e.g. encephalin, GABA, NO, etc….) Function of the peptides transmitters 1. Regulation of GIT motility 2. Regulation of the release of GIT hormones