8. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďPart of nervous system that controls
visceral functions
⢠Cardiac muscle, smooth muscle (blood
vessels, GIT, urinary bladder etc) glands
(secretions)
ďNot under voluntary control
9. Anatomy of the Motor Output inAnatomy of the Motor Output in
Sympathetic and ParasympatheticSympathetic and Parasympathetic
nervesnerves
10. ďAutonomic nervous system
⢠Two neuron chain from CNS to effector
organ
⢠Pre and postganglionic neurons
ďSomatic nervous system
⢠Single neuron connects CNS with effector
organ
12. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďGanglion
⢠Cluster of neurons outside CNS
⢠Autonomic ganglion
oSite of synapse between autonomic pre &
post ganglionic fibers
oParavertebral ganglionic chain
oPrevertebral (collateral) ganglia
13. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďCell body of preganlionic neuron
⢠Lies in CNS
oSpinal cord (sympathetic division)
oBrain and spinal cord (parasympathetic
division)
ďCell body of postganglionic neuron
⢠Lies in autonomic ganglia
14. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďSympathetic nervouss system
⢠Short preganlionic fibers
⢠Long postganglionic fibers
ďParasympathetic nervous system
⢠Long preganlionic fibers
⢠Short postganglionic fibers
17. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďAll preganlionic fibers are cholinergic
ďAll postganglionic parasympathetic
fibers are cholinergic
ďAlmost all postganglionic
sympathetic fibers are adrenergic
⢠postganglionic sympathetic fibers to
sweat glands and piloerector muscles
are cholinergic
18. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďReceptors
⢠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
oÎą adrenergic receptors (Îą1 and Îą2)
oΠadrenergic receptors (β1 and β2)
19. Muscarinic receptors in the parasympathetic
system β M1 M3, M5 M2, M5
AcetylcholineAcetylcholine
Neuroscience, Sinauer Asssoc., Inc
20. Neuroscience, Sinauer Asssoc., Inc
Adrenergic receptors in the sympathetic system
Norepinephrine
β ι1 ι2
Norepinephrine
25. Sympathetic NS
NE, EPINEPHRINE
Stimulated Inhibited
All the tissues
Îą1 A.R
Except
Heart, JGA, Lipocytes
Î1 A.R
All the tissues
β2 A.R
Except
Presynaptic Nerve Endings
Platelets, some part of GIT
Îą2 AR
36. 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 Âľg/kg/min Epinephrine and .05
Âľg/kg/min of noreepineohrine
37. Adrenal MedullaAdrenal Medulla
⢠Epinephrine affects
â more on beta
âLess on alpha
âMore metabolic effect
⢠Adrenal medulla provides back
up for sympathetic function in
addition to normal channel of
sympathetic nerves
40. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďDual supply
⢠All the viscera supplied by both the
divisions of ANS
⢠Sympathovagal balance determines the
ultimate function of the viscera
41. Functions of ANSFunctions of ANS
Sympathetic and parasympathetic
components of ANS function to
maintain homeostasis at
subconscious level -maintain stable
internal environment
42. Îą1 receptors
â˘vascular smooth muscle, on GI and bladder sphincters
and radial muscle of the eye. causes excitation
(contraction)
Îą2 receptors
â˘presynaptic nerve terminals, platelets, fat cells, walls of
GI tract causes inhibition (relaxation, dilation)
β1 receptors
â˘SA node, AV node, ventricular muscle of heart
⢠produces excitation, increases heart rate, contractility,
and conduction velocity
β2 receptors
â˘vascular smooth muscle of skeletal muscle, bronchioles,
walls of GI tract and bladder
â˘produces relaxation: dilation of vascular smooth muscle
and relaxation of bladder, bronchioles
Location of specific adrenergic receptors
45. 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
47. Sympathetic and
parasympathetic toneâ
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
49. Enteric Nervous
System
Gastrointestinal tract nervous system
Myenteric plexus
(auberbachâs)
Meissnerâs 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
51. 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
â˘pupilary dilation
â˘increase heart rate and strength of contracti
â˘increase blood pressure
â˘increase blood flow to active muscles
â˘increase rates of metabolism
â˘increased blood glucose concentration
â˘increased muscle strength
â˘increase mental activity
52. Exceptions of isolatedExceptions of isolated
Function inFunction in
SympatheicSympatheic
⢠SWEATING
⢠Muscle activiy in animals
⢠Local reflexes (skin heat)
⢠Many GIT reflexes
53. 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 ContrastâŚâŚ...
54. 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
55. Functions of ANSFunctions of ANS
ďSympathetic nervous system
⢠Prepares and mobilizes the body in
emergency (fright, fear, pain, rage etc)
⢠Fight or flight reaction
56. Functions of ANSFunctions of ANS
ďParasympathetic nervous system
⢠Conserves and stores energy -puts the
body in cool and calm state
57. Functions of ANSFunctions of ANS
Sympathetic Parasympathetic
Heart
â heart rate
â force of contraction
Heart
â heart rate
âforce of contraction
Blood vessels
Constriction
Blood vessels
No effect
Lungs
Bronchodilation
Lungs
Bronchoconstriction
GIT
â motility
Sphincter contraction
Decreased secretions
GIT
â motility
Sphincter relaxation
Increased secretions
58. 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
59. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďMass 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 âemergencyâ
60. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ď 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
61. Autonomic nervousAutonomic nervous
system (ANS)system (ANS)
ďSympathetic and parasympathetic
tone
⢠Basal rate of discharge
⢠Allows single division to adjust
stimulation level of an organ
oSympathetic tone to blood vessels