AUTONOMICAUTONOMICNERVOUS SYSTEMNERVOUS SYSTEMProf. Vajira WeerasingheProf. Vajira WeerasingheDept of PhysiologyDept of Ph...
4Autonomic nervous systemAutonomic nervous systemThe autonomic nervous system is theThe autonomic nervous system is thesub...
Autonomic (visceral motor)autonomicsomaticthis dorsalroot ganglionis sensorySomatic motor
Difference between somaticDifference between somaticmotor and autonomic motormotor and autonomic motor► Somatic motor:Soma...
7►Axon of 1Axon of 1stst((preganglionicpreganglionic) neuron leaves) neuron leavesCNS to synapse with the 2CNS to synapse ...
Divisions of the autonomic nervous systemDivisions of the autonomic nervous system►Parasympathetic divisionParasympathetic...
9Where they come fromWhere they come fromParasympathetic:craniosacralSympathetic:thoracolumbar
10Sympathetic nervous systemSympathetic nervous system“fight or flight”“fight or flight”► Also calledAlso called thoracolu...
11SympatheticSympathetic
12Parasympathetic nervous systemParasympathetic nervous system“rest & digest”“rest & digest”►Also called theAlso called th...
13Parasympathetic continuedParasympathetic continued► Cranial outflowCranial outflow III - pupils constrictIII - pupils c...
14ParasympatheticParasympathetic
NeurotransmittersNeurotransmitters►Somatic = all motor neurons release ACHSomatic = all motor neurons release ACHwhich is ...
Comparison of Sympathetic andComparison of Sympathetic andparasympathetic Systemsparasympathetic Systems
Divisions of the ANSDivisions of the ANS► Sympathetic NSSympathetic NS► ParasymatheticParasymatheticNSNS► Dual innervation...
Sympathetic nervousSympathetic nervoussystemsystem► The sympathetic division is theThe sympathetic division is the “fight-...
Parasympathetic nervous systemParasympathetic nervous system► Salivation, Lacrimation, Urination, Digestion,Salivation, La...
DifferencesDifferencesAch (N)Ach (N) Ach (M)NorSympatheticParasympatheticAdre
Neurotransmitters and ReceptorsNeurotransmitters and Receptors► Acetylcholine (ACh) and norepinephrine (NE) are theAcetylc...
Cholinergic ReceptorsCholinergic Receptors►The two types of receptors that bindThe two types of receptors that bindACh are...
Nicotinic Receptors (cholinergic)Nicotinic Receptors (cholinergic)►Nicotinic receptors are found on:Nicotinic receptors ar...
Muscarinic ReceptorsMuscarinic Receptors(cholinergic)(cholinergic)►Muscarinic receptors occur on all effectorMuscarinic re...
Adrenergic ReceptorsAdrenergic Receptors► The two types of adrenergic receptors are alphaThe two types of adrenergic recep...
Adrenergic ReceptorsAdrenergic Receptors►Norepinephrine produces its effects byNorepinephrine produces its effects bycombi...
Adrenergic ReceptorsAdrenergic Receptors►Found in:Found in: CardiovascularCardiovascular EndocrineEndocrine Gastrointes...
Alpha ReceptorsAlpha Receptors►Alpha 1: adrenergic receptors located onAlpha 1: adrenergic receptors located onpostsynapti...
Alpha 2Alpha 2►Same as the Alpha 1 but are located in theSame as the Alpha 1 but are located in thepresynaptic nerve termi...
Adrenergic ReceptorAdrenergic Receptor►Beta 1Beta 1►CardiovascularCardiovascular Cardiac muscle: increased contractilityC...
Beta 1 DrugsBeta 1 Drugs►Predominately works on vascular smoothPredominately works on vascular smoothmuscle of the heart.m...
Adrenergic ReceptorAdrenergic Receptor►Beta 2Beta 2►CardiovascularCardiovascular Dilation of blood vesselsDilation of blo...
HeartHeart►Direct stimulation of receptorsDirect stimulation of receptors Alpha 1 –Alpha 1 –►Vasoconstriction of blood ve...
Sympathetic vs parasympatheticSympathetic vs parasympathetic►Distribution on different organsDistribution on different org...
Sympathetic vs parasympatheticSympathetic vs parasympathetic►Distribution on different organsDistribution on different org...
Fig. 9.6Fig. 9.6
Sympathetic (Thoracolumbar)Sympathetic (Thoracolumbar)DivisionDivision► Preganglionic cell bodies in lateralPreganglionic ...
Parasympathetic (Craniosacral)Parasympathetic (Craniosacral)DivisionDivision► Preganglionic cell bodies inPreganglionic ce...
Sympathetic vs parasympatheticSympathetic vs parasympathetic►Actions on different organsActions on different organs
Sympathetic vs parasympatheticSympathetic vs parasympathetic►Drugs acting on receptorsDrugs acting on receptors
ParasympatheticSympathetic
salbutamol
Sympathetic vs parasympatheticSympathetic vs parasympathetic►Reflexes in different systemsReflexes in different systems
ANS reflexesANS reflexes► CVS:CVS: baroreceptor reflexbaroreceptor reflex Control of heart rateControl of heart rate ch...
ExceptionException––adrenal medullaadrenal medulla
52Adrenal glandsAdrenal glandsOn top of kidneysOn top of kidneysAdrenal medullaAdrenal medulla(inside part) is a(inside pa...
53Adrenal gland is an exceptionAdrenal gland is an exception►Synapse in glandSynapse in gland►Can cause body-wideCan cause...
InnervationInnervationAch
Another exception - SweatAnother exception - Sweatglandsglands► The sweat glands are innervated by the sympatheticThe swea...
Another exception – skeletalAnother exception – skeletalmuscle blood vesselsmuscle blood vessels►These are also innervated...
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  1. 1. AUTONOMICAUTONOMICNERVOUS SYSTEMNERVOUS SYSTEMProf. Vajira WeerasingheProf. Vajira WeerasingheDept of PhysiologyDept of Physiology
  2. 2. 4Autonomic nervous systemAutonomic nervous systemThe autonomic nervous system is theThe autonomic nervous system is thesubdivision of the peripheral nervoussubdivision of the peripheral nervoussystem that regulates body activities thatsystem that regulates body activities thatare generally not under conscious controlare generally not under conscious control
  3. 3. Autonomic (visceral motor)autonomicsomaticthis dorsalroot ganglionis sensorySomatic motor
  4. 4. Difference between somaticDifference between somaticmotor and autonomic motormotor and autonomic motor► Somatic motor:Somatic motor: Cell bodies of motor neurons reside in CNS (brain orCell bodies of motor neurons reside in CNS (brain orspinal cord)spinal cord) Their axons (sheathed in spinal nerves) extend all theTheir axons (sheathed in spinal nerves) extend all theway to their skeletal musclesway to their skeletal muscles Fast neural transmissionFast neural transmission► Autonomic system: chains of two neuronsAutonomic system: chains of two neurons 11stst= preganglionic neuron (in brain or cord)= preganglionic neuron (in brain or cord) 22ndnd= postgangionic neuron (cell body in ganglion outside= postgangionic neuron (cell body in ganglion outsideCNS)CNS) Slower because lightly or unmyelinatedSlower because lightly or unmyelinated6
  5. 5. 7►Axon of 1Axon of 1stst((preganglionicpreganglionic) neuron leaves) neuron leavesCNS to synapse with the 2CNS to synapse with the 2ndnd((postganglionicpostganglionic) neuron) neuron►Axon of 2Axon of 2ndnd((postganglionicpostganglionic) neuron) neuronextends to the organ it servesextends to the organ it servesDiagram contrasts somatic (lower) and autonomic:autonomicsomaticNote: the autonomic ganglion is motorthis dorsalroot ganglionis sensory
  6. 6. Divisions of the autonomic nervous systemDivisions of the autonomic nervous system►Parasympathetic divisionParasympathetic division►Sympathetic divisionSympathetic divisionServe most of the same organs butServe most of the same organs butcause opposing or antagonisticcause opposing or antagonisticeffectseffectscervical, thoracic, lumbar, sacral
  7. 7. 9Where they come fromWhere they come fromParasympathetic:craniosacralSympathetic:thoracolumbar
  8. 8. 10Sympathetic nervous systemSympathetic nervous system“fight or flight”“fight or flight”► Also calledAlso called thoracolumbarthoracolumbar system: all its neuronssystem: all its neuronsare in lateral horn of gray matter from T1-L2are in lateral horn of gray matter from T1-L2► Lead to every part of the body (unlike parasymp.)Lead to every part of the body (unlike parasymp.) Easy to remember that when nervous, you sweat; whenEasy to remember that when nervous, you sweat; whenafraid, hair stands on end; when excited blood pressureafraid, hair stands on end; when excited blood pressurerises (vasoconstriction): these sympathetic onlyrises (vasoconstriction): these sympathetic only Also causes: dry mouth, pupils to dilate, increased heartAlso causes: dry mouth, pupils to dilate, increased heart& respiratory rates to increase O2 to skeletal muscles,& respiratory rates to increase O2 to skeletal muscles,and liver to release glucoseand liver to release glucose► NorepinephrineNorepinephrine (noradrenaline) is(noradrenaline) isneurotransmitter released by most postganglionicneurotransmitter released by most postganglionicfibers (acetylcholine in preganglionic): “adrenergic”fibers (acetylcholine in preganglionic): “adrenergic”
  9. 9. 11SympatheticSympathetic
  10. 10. 12Parasympathetic nervous systemParasympathetic nervous system“rest & digest”“rest & digest”►Also called theAlso called the craniosacralcraniosacral systemsystembecause all its preganglionic neurons arebecause all its preganglionic neurons arein the brain stem or sacral levels of thein the brain stem or sacral levels of thespinal cordspinal cord Cranial nerves III,VII, IX and XCranial nerves III,VII, IX and X In lateral horn of gray matter from S2-S4In lateral horn of gray matter from S2-S4►Only innervate internal organs (not skin)Only innervate internal organs (not skin)►AcetylcholineAcetylcholine is neurotransmitter at endis neurotransmitter at endorgan as well as at preganglionic synapse:organ as well as at preganglionic synapse:“cholinergic”“cholinergic”
  11. 11. 13Parasympathetic continuedParasympathetic continued► Cranial outflowCranial outflow III - pupils constrictIII - pupils constrict VII - tears, nasal mucus, salivaVII - tears, nasal mucus, saliva IX – parotid salivary glandIX – parotid salivary gland X (Vagus n) – visceral organs of thorax & abdomen:X (Vagus n) – visceral organs of thorax & abdomen:►Stimulates digestive glandsStimulates digestive glands►Increases motility of smooth muscle of digestive tractIncreases motility of smooth muscle of digestive tract►Decreases heart rateDecreases heart rate►Causes bronchial constrictionCauses bronchial constriction► Sacral outflow (S2-4): form pelvic splanchnic nervesSacral outflow (S2-4): form pelvic splanchnic nerves Supply 2Supply 2ndndhalf of large intestinehalf of large intestine Supply all the pelvic (genitourinary) organsSupply all the pelvic (genitourinary) organs
  12. 12. 14ParasympatheticParasympathetic
  13. 13. NeurotransmittersNeurotransmitters►Somatic = all motor neurons release ACHSomatic = all motor neurons release ACHwhich is always stimulatorywhich is always stimulatory►Visceral = ACH & norepinephrineVisceral = ACH & norepinephrine AllAll prepreganglionicganglionic fibers release ACHfibers release ACH AllAll postpostganglionicganglionic PsNSPsNS fibers release ACHfibers release ACH Most postganglionic SNS fibers releaseMost postganglionic SNS fibers releasenorepinorepi Can be stimulatory or inhibitory basedCan be stimulatory or inhibitory basedon receptor typeson receptor types
  14. 14. Comparison of Sympathetic andComparison of Sympathetic andparasympathetic Systemsparasympathetic Systems
  15. 15. Divisions of the ANSDivisions of the ANS► Sympathetic NSSympathetic NS► ParasymatheticParasymatheticNSNS► Dual innervationDual innervation Opposing effects on theOpposing effects on thesame organsame organ► SNS is usuallySNS is usuallystimulatory (fight or flight)stimulatory (fight or flight)► PsNS is usually inhibitoryPsNS is usually inhibitory(body maint. &(body maint. &conservation of Econservation of E
  16. 16. Sympathetic nervousSympathetic nervoussystemsystem► The sympathetic division is theThe sympathetic division is the “fight-or-flight”“fight-or-flight” systemsystem► InvolvesInvolves EE activities – exercise, excitement, emergency,activities – exercise, excitement, emergency,and embarrassmentand embarrassment► Non-essential activities are dampened (GI/urinary)Non-essential activities are dampened (GI/urinary)► Promotes adjustments during exercise – blood flow toPromotes adjustments during exercise – blood flow toorgans is reduced, flow to muscles is increasedorgans is reduced, flow to muscles is increased► Its activity is illustrated by a person who is threatenedIts activity is illustrated by a person who is threatened Heart rate increases, and breathing is rapid and deepHeart rate increases, and breathing is rapid and deep The skin is cold and sweaty, and the pupils dilateThe skin is cold and sweaty, and the pupils dilate Bronchioles dilate…increasing ventilation, delivering more oxygenBronchioles dilate…increasing ventilation, delivering more oxygento cellsto cells Constriction of visceral & cutaneous bv’s (blood is shunted toConstriction of visceral & cutaneous bv’s (blood is shunted toskeletal mm)skeletal mm) Liver releases more glucose into blood to provide more readilyLiver releases more glucose into blood to provide more readilyavail. Eavail. E Targets adipocytes for lipolysisTargets adipocytes for lipolysis
  17. 17. Parasympathetic nervous systemParasympathetic nervous system► Salivation, Lacrimation, Urination, Digestion,Salivation, Lacrimation, Urination, Digestion,DefecationDefecation► Most active in non-stressful situationsMost active in non-stressful situations► Concerned with keeping body energy use lowConcerned with keeping body energy use low► Lenses of eyes accommodated for near visionLenses of eyes accommodated for near vision► Its activity is illustrated in a person who relaxesIts activity is illustrated in a person who relaxesafter a mealafter a meal Blood pressure, heart rate, and respiratory rates areBlood pressure, heart rate, and respiratory rates arelowlow Gastrointestinal tract activity is highGastrointestinal tract activity is high The skin is warm and the pupils are constrictedThe skin is warm and the pupils are constricted
  18. 18. DifferencesDifferencesAch (N)Ach (N) Ach (M)NorSympatheticParasympatheticAdre
  19. 19. Neurotransmitters and ReceptorsNeurotransmitters and Receptors► Acetylcholine (ACh) and norepinephrine (NE) are theAcetylcholine (ACh) and norepinephrine (NE) are thetwo major neurotransmitters of the ANStwo major neurotransmitters of the ANS► ACh is released by all preganglionic axons and allACh is released by all preganglionic axons and allparasympathetic postganglionic axonsparasympathetic postganglionic axons► Cholinergic fibersCholinergic fibers – ACh-releasing fibers– ACh-releasing fibers► Adrenergic fibersAdrenergic fibers – sympathetic postganglionic– sympathetic postganglionicaxons that release NEaxons that release NE► Neurotransmitter effects can be excitatory or inhibitoryNeurotransmitter effects can be excitatory or inhibitorydepending upon the receptor typedepending upon the receptor type
  20. 20. Cholinergic ReceptorsCholinergic Receptors►The two types of receptors that bindThe two types of receptors that bindACh areACh are nicotinicnicotinic andand muscarinicmuscarinic►These are named after drugs that bindThese are named after drugs that bindto them and mimic ACh effectsto them and mimic ACh effects
  21. 21. Nicotinic Receptors (cholinergic)Nicotinic Receptors (cholinergic)►Nicotinic receptors are found on:Nicotinic receptors are found on: Motor end plates (somatic targets)Motor end plates (somatic targets) All ganglionic neurons of both sympatheticAll ganglionic neurons of both sympatheticand parasympathetic divisionsand parasympathetic divisions The hormone-producing cells of theThe hormone-producing cells of theadrenal medullaadrenal medulla►The effect of ACh binding to nicotinicThe effect of ACh binding to nicotinicreceptors isreceptors is always stimulatoryalways stimulatory
  22. 22. Muscarinic ReceptorsMuscarinic Receptors(cholinergic)(cholinergic)►Muscarinic receptors occur on all effectorMuscarinic receptors occur on all effectorcells stimulated by postganglioniccells stimulated by postganglioniccholinergic fiberscholinergic fibers►The effect of ACh binding:The effect of ACh binding: Can be either inhibitory or excitatoryCan be either inhibitory or excitatory Depends on the receptor typeDepends on the receptor type of theof thetarget organtarget organ
  23. 23. Adrenergic ReceptorsAdrenergic Receptors► The two types of adrenergic receptors are alphaThe two types of adrenergic receptors are alphaand betaand beta► Each type has two or three subclassesEach type has two or three subclasses((αα11,, αα22,, ββ11,, ββ22 ,, ββ33))► Effects of NE binding to:Effects of NE binding to: αα receptors is generally stimulatoryreceptors is generally stimulatory ββ receptors is generally inhibitoryreceptors is generally inhibitory► A notable exception – NE binding toA notable exception – NE binding to ββ receptors ofreceptors ofthe heart is stimulatorythe heart is stimulatory
  24. 24. Adrenergic ReceptorsAdrenergic Receptors►Norepinephrine produces its effects byNorepinephrine produces its effects bycombining with adrenergic receptorscombining with adrenergic receptors AlphaAlpha BetaBeta
  25. 25. Adrenergic ReceptorsAdrenergic Receptors►Found in:Found in: CardiovascularCardiovascular EndocrineEndocrine GastrointestinalGastrointestinal GenitourinaryGenitourinary RespiratoryRespiratory OcularOcular
  26. 26. Alpha ReceptorsAlpha Receptors►Alpha 1: adrenergic receptors located onAlpha 1: adrenergic receptors located onpostsynaptic effector cells.postsynaptic effector cells. Smooth muscles of blood vessels: ConstrictionSmooth muscles of blood vessels: Constriction►Arteriolar constrictionArteriolar constriction Bladder sphincterBladder sphincter PenisPenis UterusUterus Pupillary muscles of irisPupillary muscles of iris
  27. 27. Alpha 2Alpha 2►Same as the Alpha 1 but are located in theSame as the Alpha 1 but are located in thepresynaptic nerve terminals.presynaptic nerve terminals.
  28. 28. Adrenergic ReceptorAdrenergic Receptor►Beta 1Beta 1►CardiovascularCardiovascular Cardiac muscle: increased contractilityCardiac muscle: increased contractilityincreased force of contractionincreased force of contraction Atrioventricular node: increased heart rateAtrioventricular node: increased heart rate Sinoatrial node: increase in heart rateSinoatrial node: increase in heart rate►EndocrineEndocrine PancreasPancreas
  29. 29. Beta 1 DrugsBeta 1 Drugs►Predominately works on vascular smoothPredominately works on vascular smoothmuscle of the heart.muscle of the heart.
  30. 30. Adrenergic ReceptorAdrenergic Receptor►Beta 2Beta 2►CardiovascularCardiovascular Dilation of blood vesselsDilation of blood vessels►EndocrineEndocrine►Uterine relaxationUterine relaxation►Respiratory: dilation of bronchial musclesRespiratory: dilation of bronchial muscles
  31. 31. HeartHeart►Direct stimulation of receptorsDirect stimulation of receptors Alpha 1 –Alpha 1 –►Vasoconstriction of blood vessels which increasesVasoconstriction of blood vessels which increasesblood pressureblood pressure►Pressor or vasopressor effect to maintain bloodPressor or vasopressor effect to maintain bloodpressurepressure Beta 1Beta 1►Increased force of myocardial contractionIncreased force of myocardial contraction►Increased speed of electrical conduction in the heart.Increased speed of electrical conduction in the heart.
  32. 32. Sympathetic vs parasympatheticSympathetic vs parasympathetic►Distribution on different organsDistribution on different organs►Actions on different organsActions on different organs►Drugs acting on receptorsDrugs acting on receptors►Reflexes in different systemsReflexes in different systems
  33. 33. Sympathetic vs parasympatheticSympathetic vs parasympathetic►Distribution on different organsDistribution on different organs
  34. 34. Fig. 9.6Fig. 9.6
  35. 35. Sympathetic (Thoracolumbar)Sympathetic (Thoracolumbar)DivisionDivision► Preganglionic cell bodies in lateralPreganglionic cell bodies in lateralhorns of spinal cord T1-L2:horns of spinal cord T1-L2:thoracolumbarthoracolumbar► Preganglionic axons pass throughPreganglionic axons pass throughventral roots toventral roots to whitewhite ramiramicommunicantescommunicantes to theto theretroperitonealretroperitoneal sympatheticsympatheticchain gangliachain ganglia
  36. 36. Parasympathetic (Craniosacral)Parasympathetic (Craniosacral)DivisionDivision► Preganglionic cell bodies inPreganglionic cell bodies innuclei of brainstem or lateralnuclei of brainstem or lateralparts of spinal cord gray matterparts of spinal cord gray matterfrom S2-S4from S2-S4 Preganglionic axons fromPreganglionic axons frombrain pass to terminalbrain pass to terminalganglia through cranialganglia through cranialnerves III, VII, IX and Xnerves III, VII, IX and X Preganglionic axons fromPreganglionic axons fromsacral region pass throughsacral region pass throughpelvic nervespelvic nerves to terminalto terminalgangliaganglia► Terminal gangliaTerminal ganglia locatedlocatednear organ innervated ornear organ innervated orembedded in wall of organembedded in wall of organ
  37. 37. Sympathetic vs parasympatheticSympathetic vs parasympathetic►Actions on different organsActions on different organs
  38. 38. Sympathetic vs parasympatheticSympathetic vs parasympathetic►Drugs acting on receptorsDrugs acting on receptors
  39. 39. ParasympatheticSympathetic
  40. 40. salbutamol
  41. 41. Sympathetic vs parasympatheticSympathetic vs parasympathetic►Reflexes in different systemsReflexes in different systems
  42. 42. ANS reflexesANS reflexes► CVS:CVS: baroreceptor reflexbaroreceptor reflex Control of heart rateControl of heart rate chemoreceptor reflexchemoreceptor reflex► GIT:GIT: GIT secretions and motilityGIT secretions and motility► Other:Other: Urinary bladder controlUrinary bladder control Sexual reflexesSexual reflexes SweatingSweating Other visceral reflexesOther visceral reflexes
  43. 43. ExceptionException––adrenal medullaadrenal medulla
  44. 44. 52Adrenal glandsAdrenal glandsOn top of kidneysOn top of kidneysAdrenal medullaAdrenal medulla(inside part) is a(inside part) is amajor organ ofmajor organ ofthe sympatheticthe sympatheticnervous systemnervous system
  45. 45. 53Adrenal gland is an exceptionAdrenal gland is an exception►Synapse in glandSynapse in gland►Can cause body-wideCan cause body-widerelease of epinephrinerelease of epinephrine(adrenaline) and(adrenaline) andnorepinephrinenorepinephrine(noradrenaline) in an(noradrenaline) in anextreme emergencyextreme emergency(adrenaline “rush” or(adrenaline “rush” orsurge)surge)
  46. 46. InnervationInnervationAch
  47. 47. Another exception - SweatAnother exception - Sweatglandsglands► The sweat glands are innervated by the sympatheticThe sweat glands are innervated by the sympatheticnervous system (part of the fight or flight responsenervous system (part of the fight or flight responsesystem)system)► Preganglionic neuron is short, originates from thePreganglionic neuron is short, originates from thethoracolumbar region of the spinal cord, usesthoracolumbar region of the spinal cord, usesacetylcholine as its neurotransmitter (nicotinic )acetylcholine as its neurotransmitter (nicotinic )► Postganglionic neuron for sweat gland innervationPostganglionic neuron for sweat gland innervationdiffers from other sympathetic postganglionic neuronsdiffers from other sympathetic postganglionic neuronsin that it releases acetylcholine to act on muscarinicin that it releases acetylcholine to act on muscarinicreceptorsreceptors
  48. 48. Another exception – skeletalAnother exception – skeletalmuscle blood vesselsmuscle blood vessels►These are also innervated by sympatheticThese are also innervated by sympatheticcholinergic fibrescholinergic fibres
  49. 49. 58Summary

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