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Chapter 14.docx - Autonomic Nervous System (ANS) • ANS -...

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Autonomic Nervous System (ANS)ANS - system of motor division of the PNS that controls visceral activitieswith thegoal of maintaining hemostasis.Neurons thatinnervates smooth and cardiac muscles, & glands.AKA Involuntary nervous system or general visceral motor systemComparison of the Somatic and AutonomicSomatic nervous system1.Voluntary, provides motor fibers toskeletalmuscle.2.Single motor neuron forms the efferent pathwayfrom the CNS to the effectors3.Acetylcholine,(neurotransmitter for somatic)stimulatory to skeletal muscle fibers.Autonomic nervous system1.Involuntary or visceral motor, providemo-tor fibers to smooth and cardiac musclesand glands.2.Efferentpathway consist of 2 neuron chaina.Preganglionic neurons; in CNSb.Ganglionic neurons in a ganglion.3.Norepinephrine and acetylcholine (neuro-transmitters) may cause excitation or inhibi-tion.Autonomic Nervous System Division2 divisions parasympathetic and sympathetic, exert antagonistic effects on many of the same target organs.Parasympathetic ROLE1)Resting and digesting system2)Conserves body energy3)Maintains body activities @ basal levels; minimalto sustain life.4)Effects:a)Pupillary constriction,b)Glandular secretion,c)Increased digestive tract motility,d)Smooth muscle activity leading to eliminationfeces/urine.Sympathetic ROLE1)4 F’s Flight, Fight, freight and Sex. (F***)2)AKA flight or fight System3)Prepares the body for activity.4)Responses:a)Dilated pupilsb)Increased heart rate.c)Increased blood pressure.d)Dilation of the bronchioles of the lungs.e)Increased blood glucose levelsf)Sweating.*During exercise, sympathetic vasoconstriction shuntsblood from the skin and digestive viscera to the heart,brain, and skeletal muscles*
ANS AnatomyAnatomical DivisionsGanglions, Pre/PostNerve and FiberParasympathetic(Craniosacral) divisionPreganglionic;AKA, Presynaptic nerve.From synapse to post-ganglion.Postganglion;AKA, post synaptic nerve.Axon enters the organ.Parasympathetic preganglionicneurons arise from the brainstem and from (S2-S4) region ofthe spinal cord (SC)=cranial-sacral region.Preganglionic fiber synapse w/postganglionic neurons in termi-nal/autonomic ganglia located(intramural ganglia) or close totheir effector organ.Preganglionic fiber= longAxon DONOT travel withinrami communicants.Postganglionic fiber=shortCranial fibers arise from the brain stem nu-clei ofCNIII (OCULOMOTOR)------------ HEADCNVII(FACIAL)-----------------------HEADCNIX ( GLOSSOPHARYNGEAL)-THROATCNX( VAGUS)---------------------- AB-DOMENCNX—VAGUS serves all organs of the tho-rax & abdomen.10% FUNCTION comes from CN III, VII,IX.90% FUNCTION comes from CNX.Sacral fibers (S2-S4)ISSUE FORM THE LATERIAL REGIONOF CORD AND THE PELVIC SPLANCH-NIC NERVE, THAT INNERVATE THEPELVIC VISCERA.

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Term
Spring
Professor
DrRabacchi

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