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Autonomic NervousAutonomic Nervous
SystemSystem
Dr Ayyaz AhmedDr Ayyaz Ahmed
AP PhysiologyAP Physiology
Learning ObjectivesLearning Objectives
• Outline the functions of ANS
• Describe the functions of
Sympathetic Nervous Syst...
All smooth muscles
All Glandular structures Myocardium
General Visceral Efferent
ANSANS
Innervates all innervated
structures in the body except
NMJ of SKM
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Part of nervous system that controls
visceral functions
• Car...
Anatomy of the Motor Output inAnatomy of the Motor Output in
Sympathetic and ParasympatheticSympathetic and Parasympatheti...
Autonomic nervous system
• Two neuron chain from CNS to effector
organ
• Pre and postganglionic neurons
Somatic nervous ...
NeurotransmittersNeurotransmitters
involvedinvolved
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Ganglion
• Cluster of neurons outside CNS
• Autonomic ganglio...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Cell body of preganlionic neuron
• Lies in CNS
oSpinal cord (...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Sympathetic nervouss system
• Short preganlionic fibers
• Lon...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Cholinergic fibers
• Fibers releasing acetylcholine
Adrenerg...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
All preganlionic fibers are cholinergic
All postganglionic p...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Receptors
• Nicotinic receptors -in autonomic ganglia
• Musca...
Muscarinic receptors in the parasympathetic
system β M1 M3, M5 M2, M5
AcetylcholineAcetylcholine
Neuroscience, Sinauer Ass...
Neuroscience, Sinauer Asssoc., Inc
Adrenergic receptors in the sympathetic system
Norepinephrine
β α1 α2
Norepinephrine
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Sympathetic division
• Thoracolumbar (T1to L2)
Parasympathet...
Sympathetic NS
NE, EPINEPHRINE
Stimulated Inhibited
All the tissues
α1 A.R
Except
Heart, JGA, Lipocytes
Β1 A.R
All the tis...
DP- Alpha 1 Receptors
Cilliaris- Beta 2 Receptors
Skin
Vessels Stimulated
Alpha 1 Receptors
Respiratory System
Blood Vessels
α1
Bronchial secretion Decreases
Mast Cells
β2
Bronchial Smooth
β2
Adrenal medulla
Stimulation of sympathetic innervation of
adrenal medulla causes release of large
quantities of epinephrin...
Adrenal MedullaAdrenal Medulla
• Epinephrine affects
– more on beta
–Less on alpha
–More metabolic effect
• Adrenal medull...
Thank You
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Dual supply
• All the viscera supplied by both the
divisions ...
Functions of ANSFunctions of ANS
Sympathetic and parasympathetic
components of ANS function to
maintain homeostasis at
sub...
α1 receptors
•vascular smooth muscle, on GI and bladder sphincters
and radial muscle of the eye. causes excitation
(contra...
Co-Transmission
Acetylcholine and Norepinephrine play
important, but not exclusive, roles
in the autonomic nervous system
Sweat glandsSweat glands
• Sympathetic fires supply them. If
stimulated copious sweating
• Acetylcholine is neurotransmiit...
Stimulus RateStimulus Rate
• Low frequency required to fully
activate ANS as compared to
Skeletal nervous system
Sympathetic and
parasympathetic tone”
Continual basal activity of the
sympathetic
and parasympathetic systems allows
eithe...
Denervation
supersensitivity
Receptor up regulation?
Enteric Nervous
System
Gastrointestinal tract nervous system
Myenteric plexus
(auberbach’s)
Meissner’s plexus
(submucosal)...
Autonomic Reflexes
cardiovascular reflexes
gastrointestinal reflexes
bladder emptying
sweating
blood glucose
concentration...
Alarm or Stress response
Mass discharge of sympathetic system allows
the body to make maximal use of its resource
thereby ...
Exceptions of isolatedExceptions of isolated
Function inFunction in
SympatheicSympatheic
• SWEATING
• Muscle activiy in an...
Parasympathetic System Usually CausesParasympathetic System Usually Causes
specific localized responsesspecific localized ...
Hypothalamus is critical
for coordinating autonomic
output.
It projects to several
brainstem nuclei and
coordinates autono...
Functions of ANSFunctions of ANS
Sympathetic nervous system
• Prepares and mobilizes the body in
emergency (fright, fear,...
Functions of ANSFunctions of ANS
Parasympathetic nervous system
• Conserves and stores energy -puts the
body in cool and ...
Functions of ANSFunctions of ANS
Sympathetic Parasympathetic
Heart
↑ heart rate
↑ force of contraction
Heart
↓ heart rate
...
Functions of ANSFunctions of ANS
Sympathetic Parasympathetic
Salivary glands
Stimulates secretion
Salivary glands
Stimulat...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Mass discharge of sympathetic
system
• Simultaneous discharge...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
 Mass discharge of sympathetic system
• Increased BP
• Increa...
Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
Sympathetic and parasympathetic
tone
• Basal rate of discharg...
Thank You
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
Physiology ANS
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Physiology ANS

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Physiology ANS

  1. 1. Autonomic NervousAutonomic Nervous SystemSystem Dr Ayyaz AhmedDr Ayyaz Ahmed AP PhysiologyAP Physiology
  2. 2. Learning ObjectivesLearning Objectives • Outline the functions of ANS • Describe the functions of Sympathetic Nervous System
  3. 3. All smooth muscles All Glandular structures Myocardium General Visceral Efferent
  4. 4. ANSANS Innervates all innervated structures in the body except NMJ of SKM
  5. 5. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Part of nervous system that controls visceral functions • Cardiac muscle, smooth muscle (blood vessels, GIT, urinary bladder etc) glands (secretions) Not under voluntary control
  6. 6. Anatomy of the Motor Output inAnatomy of the Motor Output in Sympathetic and ParasympatheticSympathetic and Parasympathetic nervesnerves
  7. 7. Autonomic nervous system • Two neuron chain from CNS to effector organ • Pre and postganglionic neurons Somatic nervous system • Single neuron connects CNS with effector organ
  8. 8. NeurotransmittersNeurotransmitters involvedinvolved
  9. 9. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Ganglion • Cluster of neurons outside CNS • Autonomic ganglion oSite of synapse between autonomic pre & post ganglionic fibers oParavertebral ganglionic chain oPrevertebral (collateral) ganglia
  10. 10. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Cell body of preganlionic neuron • Lies in CNS oSpinal cord (sympathetic division) oBrain and spinal cord (parasympathetic division) Cell body of postganglionic neuron • Lies in autonomic ganglia
  11. 11. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Sympathetic nervouss system • Short preganlionic fibers • Long postganglionic fibers Parasympathetic nervous system • Long preganlionic fibers • Short postganglionic fibers
  12. 12. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Cholinergic fibers • Fibers releasing acetylcholine Adrenergic fibers • Fibers releasing noradrenalin
  13. 13. Autonomic nervousAutonomic nervous system (ANS)system (ANS) All preganlionic fibers are cholinergic All postganglionic parasympathetic fibers are cholinergic Almost all postganglionic sympathetic fibers are adrenergic • postganglionic sympathetic fibers to sweat glands and piloerector muscles are cholinergic
  14. 14. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Receptors • Nicotinic receptors -in autonomic ganglia • Muscarinic receptors -in effector organs stimulated by postganglionic cholinergic fibers • Adrenergic receptors -in effector organs stimulated by postganglionic adrenergic fibers oα adrenergic receptors (α1 and α2) oΒ adrenergic receptors (β1 and β2)
  15. 15. Muscarinic receptors in the parasympathetic system β M1 M3, M5 M2, M5 AcetylcholineAcetylcholine Neuroscience, Sinauer Asssoc., Inc
  16. 16. Neuroscience, Sinauer Asssoc., Inc Adrenergic receptors in the sympathetic system Norepinephrine β α1 α2 Norepinephrine
  17. 17. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Sympathetic division • Thoracolumbar (T1to L2) Parasympathetic division • Craniosacral (III, VII, IX, X cranial nerves & S1to S4)
  18. 18. Sympathetic NS NE, EPINEPHRINE Stimulated Inhibited All the tissues α1 A.R Except Heart, JGA, Lipocytes Β1 A.R All the tissues β2 A.R Except Presynaptic Nerve Endings Platelets, some part of GIT α2 AR
  19. 19. DP- Alpha 1 Receptors Cilliaris- Beta 2 Receptors
  20. 20. Skin Vessels Stimulated Alpha 1 Receptors
  21. 21. Respiratory System Blood Vessels α1 Bronchial secretion Decreases Mast Cells β2 Bronchial Smooth β2
  22. 22. Adrenal medulla Stimulation of sympathetic innervation of adrenal medulla causes release of large quantities of epinephrine (80%) and norepinephrine (20%) Effect lasts 5-10 times longer Sympathetic tone caused by basal secretion from adrenal medulla (.2 µg/kg/min Epinephrine and .05 µg/kg/min of noreepineohrine
  23. 23. Adrenal MedullaAdrenal Medulla • Epinephrine affects – more on beta –Less on alpha –More metabolic effect • Adrenal medulla provides back up for sympathetic function in addition to normal channel of sympathetic nerves
  24. 24. Thank You
  25. 25. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Dual supply • All the viscera supplied by both the divisions of ANS • Sympathovagal balance determines the ultimate function of the viscera
  26. 26. Functions of ANSFunctions of ANS Sympathetic and parasympathetic components of ANS function to maintain homeostasis at subconscious level -maintain stable internal environment
  27. 27. α1 receptors •vascular smooth muscle, on GI and bladder sphincters and radial muscle of the eye. causes excitation (contraction) α2 receptors •presynaptic nerve terminals, platelets, fat cells, walls of GI tract causes inhibition (relaxation, dilation) β1 receptors •SA node, AV node, ventricular muscle of heart • produces excitation, increases heart rate, contractility, and conduction velocity β2 receptors •vascular smooth muscle of skeletal muscle, bronchioles, walls of GI tract and bladder •produces relaxation: dilation of vascular smooth muscle and relaxation of bladder, bronchioles Location of specific adrenergic receptors
  28. 28. Co-Transmission Acetylcholine and Norepinephrine play important, but not exclusive, roles in the autonomic nervous system
  29. 29. Sweat glandsSweat glands • Sympathetic fires supply them. If stimulated copious sweating • Acetylcholine is neurotransmiiter except palms and soles which are adrenergic • Overall control is parasympathetic via hypothalamus so sweating could be called parasympathetic function
  30. 30. Stimulus RateStimulus Rate • Low frequency required to fully activate ANS as compared to Skeletal nervous system
  31. 31. Sympathetic and parasympathetic tone” Continual basal activity of the sympathetic and parasympathetic systems allows either branch of the ANS to increase or decrease its activity of a stimulated organ If tone lost intrinsic compensation in some time
  32. 32. Denervation supersensitivity Receptor up regulation?
  33. 33. Enteric Nervous System Gastrointestinal tract nervous system Myenteric plexus (auberbach’s) Meissner’s plexus (submucosal)The Enteric Nervous System can function on its own but is most often controlled by the sympathetic and parasympathetic systems Contains more neurons than the spinal cord and uses many different neurotransmitters and neuromodulator approaching the complexity of the CNS
  34. 34. Autonomic Reflexes cardiovascular reflexes gastrointestinal reflexes bladder emptying sweating blood glucose concentration sexual reflexes
  35. 35. Alarm or Stress response Mass discharge of sympathetic system allows the body to make maximal use of its resource thereby enhancing its chances for survival •pupilary dilation •increase heart rate and strength of contracti •increase blood pressure •increase blood flow to active muscles •increase rates of metabolism •increased blood glucose concentration •increased muscle strength •increase mental activity
  36. 36. Exceptions of isolatedExceptions of isolated Function inFunction in SympatheicSympatheic • SWEATING • Muscle activiy in animals • Local reflexes (skin heat) • Many GIT reflexes
  37. 37. Parasympathetic System Usually CausesParasympathetic System Usually Causes specific localized responsesspecific localized responses Parasympathetic cardiovascular reflexes usually act only on the heart to control its rate of beating Examples:Examples: timulation of secretion in mouth while not ffecting stomach, although sometimes they occ ogether In Contrast……...
  38. 38. Hypothalamus is critical for coordinating autonomic output. It projects to several brainstem nuclei and coordinates autonomic function with feeding, thermoreg.,water balance, circadium rhythm, sex drive, etc., and thus plays a dominant role in integrating higher cortical areas and autonomic function.panic attacks, emotional stress, cognitive activity Medullary, pontine and mesencephalicMedullary, pontine and mesencephalic control of ANS and their supervision bycontrol of ANS and their supervision by HYPOTHALAMUSHYPOTHALAMUS
  39. 39. Functions of ANSFunctions of ANS Sympathetic nervous system • Prepares and mobilizes the body in emergency (fright, fear, pain, rage etc) • Fight or flight reaction
  40. 40. Functions of ANSFunctions of ANS Parasympathetic nervous system • Conserves and stores energy -puts the body in cool and calm state
  41. 41. Functions of ANSFunctions of ANS Sympathetic Parasympathetic Heart ↑ heart rate ↑ force of contraction Heart ↓ heart rate ↓force of contraction Blood vessels Constriction Blood vessels No effect Lungs Bronchodilation Lungs Bronchoconstriction GIT ↓ motility Sphincter contraction Decreased secretions GIT ↑ motility Sphincter relaxation Increased secretions
  42. 42. Functions of ANSFunctions of ANS Sympathetic Parasympathetic Salivary glands Stimulates secretion Salivary glands Stimulates secretion Sweat glands Copious secretion Sweat glands Sweating on palms only Eye Papillary dilation Flattening of lens Eye Papillary constriction Thickening of lens Urinary bladder Relaxation of bladder wall Sphincter contraction Urinary bladder Contraction of bladder wall Sphincter relaxation
  43. 43. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Mass discharge of sympathetic system • Simultaneous discharge of all portions of sympathetic nervous system as a unit • Due to activation of hypothalamus as a result of fright, fear or pain • Also called alarm or stress response of the body • Prepares the body for ‘emergency’
  44. 44. Autonomic nervousAutonomic nervous system (ANS)system (ANS)  Mass discharge of sympathetic system • Increased BP • Increased blood flow to active muscles • Less blood flow to skin and GIT • Increased rate of cellular metabolism • Increased glycogenolysis and lipolysis • Increased muscle strength • Increased mental activity • Papillary dilation • Increased respiratory rate
  45. 45. Autonomic nervousAutonomic nervous system (ANS)system (ANS) Sympathetic and parasympathetic tone • Basal rate of discharge • Allows single division to adjust stimulation level of an organ oSympathetic tone to blood vessels
  46. 46. Thank You

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