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The Autonomic Nervous The Autonomic Nervous System (ANS) System (ANS) Chapter 17 Chapter 17

The Autonomic Nervous System (ANS) Chapter 17. Autonomic Nervous System (ANS) Motor regulation of smooth muscle, cardiac muscle, glands & adipose tissue

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  • The Autonomic Nervous System (ANS)Chapter 17

  • Autonomic Nervous System (ANS)Motor regulation of smooth muscle, cardiac muscle, glands & adipose tissue (visceral effectors) through stimulation of visceral efferent fibers Sympathetic () division fight or flight response Parasympathetic (P) division rest & repose (conserve & restore) responsedual innervation if organ receives both & P, one division excites, the other inhibits activity

  • Overview of ANS anatomySomatic efferent:CNSSomatic motor neuronSkeletal muscle

  • Sympathetic cell bodies of preganglionic neurons in lateral gray horns of spinal cord T1-L2 (thoracolumbar division) axons of pregg neurons exit with spinal nerves into white ramus (part of rami communicantes) to travel to: sympathetic chain ganglion, or collateral (prevertebral) ganglion,& adrenal medulla pregg fibers release Ach postgg neurons usually release norepinephrine (NE) effects on visceral effectors usually excitatory but depend upon specific receptor present ( or )

  • Sympathetic:Preganglionic neuronPostganglionic neuronVisceral effector(myelinated, cholinergic)(excitatory synapse)unmyelinatedEffect may be excitatory or inhibitory depending on receptorsLateral gray horns T1-L2 Chain ganglionPrevertebral ganglionAlpha() or beta ()

  • Parasympathetic cell bodies of preganglionic neurons found in cranial nerve nuclei (III, VII, IX, X) & lateral gray horns S2-S4 (craniosacral division) pregg P neurons travel to terminal ganglion (close to) or intramural ganglion (within wall) of effector both pre & postganglionic P fibers release Ach effects on organ depend on specific receptor present (nicotinic or muscarinic)

  • Parasympathetic:Preganglionic neuronPostganglionic neuronVisceral effector(myelinated, cholinergic)(excitatory synapse)unmyelinatedEffect may be excitatory or inhibitory depending on receptorsCNs (III, VII, IX, X) & Lateral gray horns S2-S4 Terminal ganglionIntramural ganglionNicotinic or Muscarinic

  • Autonomic Nervous SystemMental activityPupilsLacrimal glandsSalivary glands

    Sweat glandsBronchiolesHeartCoronary arteriolesBlood glucose/lipidsStomach motilityAdrenal glandsKidney outputGastrointestinal glandsIntestinal motilityAbdominal arteriolesBladder toneAnal/urethral sphinctersGenitals

    Skin blood vesselsSkeletal muscleSympathetic, adrenergic(thoracolumbar)Parasympathetic, cholinergic(craniosacral)IncreasesDilated

    Decreases production

    Increases productionDilatedIncreases rateDilatedIncreasesDecreasesIncreases productionDecreasesDecreases productionDecreasesConstrictedDecreases (relaxes muscle)Increased toneEjaculation

    ConstrictedVessels dilated/increases energy production and use

    -----ConstrictedTear productionIncreases production

    -----ConstrictedDecreases rate----------Increases-----IncreasesIncreases productionIncreases----- (dilated)IncreasesRelaxesErection

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  • Activities of the ANSEffects of Sympathetic Activation -fight or flight response (energy expenditure): increased cardiovascular & respiratory activity increased blood flow to brain (increased alertness), skeletal muscles, heart muscle, lungs increased visual acuity (pupil dilation) release of energy reserves from adipose, liver, & skeletal muscles decrease in non-essential functions (ie. digestion) release of Epi & NE from adrenal medullae to continue effects

  • Activities of the ANSEffects of Parasympathetic Activation -rest & repose response (conserve & restore energy): decreased cardiovascular & respiratory activityincreased GI motility & enzyme secretionpupil constriction nutrient uptake & energy storage into adipose, liver, & skeletal muscles (glycogen)

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