Autonomic Nervous System

1. AUTONOMIC NERVOUS SYSTEM
Presented By:
Dr. SAPNA VADERA
Dept. of OMFS,
VSPM’s DCRC, Nagpur
Guided By:
Dr. S.R.SHENOI
Prof. And Head, Dept. Of OMFS,
VSPM’s DCRC, Nagpur

2. Contents…
• Introduction
• Comparison b/w somatic and autonomic
nervous system
• Divisions of ANS
• Comparison b/w sympathetic and
parasympathetic nervous system
• Autonomic tone

3. Contents…
• Ganglions
Sympathetic nervous system
Parasympathetic nervous system
• Dual innervations
• Neurotransmitters
• Pharmacology
• Applied aspects
• Conclusion
• References

4. Contents…
Introduction…

5. Comparison …

6. Comparison …
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

7. AUTONOMIC
NERVOUS SYSTEM

8. Striking characteristics of the ANS
The rapidity and intensity.
• Within 3 to 5 seconds- increases heart rate to twice
normal.
• Within 10 to 15 seconds the arterial pressure
doubled.
• The arterial pressure can be decreased low enough
within 10 to 15 seconds to cause fainting.
• Sweating can begin within seconds, and the urinary
bladder may empty involuntarily, within seconds.
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

9. Central Control of ANS
• Cerebral cortex through the hypothalamus
and reticular formation
• Brain stem - reflexes for heart rate and BP
• Spinal cord - reflexes for urination,
defecation and erection
Taylor EW, Jordan D, Coote JH: Central control of the cardiovascular and
respiratory systems and their interactions in vertebrates. Physiol Rev 79:855,

10. Autonomic Visceral Reflex Arc
Taylor EW, Jordan D, Coote JH: Central control of the cardiovascular and respiratory systems and their
interactions in vertebrates. Physiol Rev 79:855, 1999.

11. • Two divisions: Sympathetic and
Parasympathetic
• Usually two systems work
together to maintain a balanced
state or homeostasis in the body
Comparison …
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

12. Sympathetic and Parasympathetic ‘tone’

13. SYMPATHETIC NERVOUS SYSTEM
• Acts in times of emergency such as ‘FRIGHT’ or ‘FLIGHT’
• Prepares the body to act
• Increases heart rate and respiration
• Raises blood pressure
• Slows activity in the digestive tract
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

14. PARASYMPATHETIC NERVOUS SYSTEM
• Counteracts the actions of the sympathetic after the
emergency
• Dominates in quite and relaxed conditions
• ‘House keeping functions’ – digestion and micturition
• Slows the heart rate and respiration
• Lowers the blood pressure

15. Two Cell Motor Pathway
• The first is the preganglionic neuron,
whose cell body is located in the brain or
spinal cord
– In the sympathetic division, the cell
body is located in the lateral grey
horns (thoraco-lumbar)
– In the parasympathetic division, the
cell body is located in various nuclei
of brain stem or in the lateral grey
horns (sacral)
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600

16. Two Cell Motor Pathway
• The second is the postganglionic neuron,
whose cell body is in an autonomic ganglion
- The postganglionic fiber sends
impulses to a target organ
- The effects at the target organ are due
to type of neurotransmitter and specific
cell surface receptors on the effector
cells
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

17. Two Cell Motor Pathway
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

18. SYMPATHETIC PARASYMPATHETIC
PREGANGLIONIC FIBRES THORACOLUMBAR DIVISION CRANIOSACRAL DIVISION
LENGTH OF PREGANGLIONIC
AXONS
SHORT LONG
PREGANGLIONIC FIBRES TRAVEL
IN
VENTRAL ROOT OF A SPINAL
NERVE
CRANIAL NERVE OR VENTRAL
ROOT OF A SPINAL NERVE
GANGLION
PARAVERTEBRAL GANGLION AND
PREVERTEBRAL GANGLION
TERMINAL GANGLION
THE PREGANGLIONIC AXON
SYNAPSES WITH:
A LARGE NUMBER OF
POSTGANGLIONIC NEURONS
A SMALL NUMBER OF
POSTGANGLIONIC NEURONS
EFFECTS WIDESPREAD NARROW
LENGTH OF POSTGANGLIONIC
AXONS
LONG SHORT
GENERAL DESCRIPTION OF
EFFECTS
"FIGHT-OR FLIGHT" RESPONSE "HOUSEKEEPING"
MOST BODY STRUCTURES
RECEIVE DUAL INNERVATION, BUT
A FEW ARE INNERVATED BY ONE
DIVISION ONLY
SWEAT GLANDS, ARRECTOR PILI
MUSCLES, FAT CELLS, CUTANEOUS
BLOOD VESSELS
LACRIMAL (TEAR) GLANDS

19. SYMPATHETIC NERVOUS SYSTEM

20. PARASYMPATHETIC NERVOUS SYSTEM

21. The Autonomic Nervous System
Structure Sympathetic Stimulation Parasympathetic Stimulation
Iris (eye muscle) Pupil dilation Pupil constriction
Salivary Glands Saliva production reduced Saliva production increased
Oral/Nasal
Mucosa
Mucus production reduced Mucus production increased
Heart
Heart rate and force
increased
Heart rate and force decreased
Lung Bronchial muscle relaxed Bronchial muscle contracted
Stomach Peristalsis reduced
Gastric juice secreted; motility
increased
Small Intestine Motility reduced Digestion increased

22. Large Intestine Motility reduced Secretions and motility increased
Liver
Increased conversion of
glycogen to glucose
Kidney Decreased urine secretion Increased urine secretion
Adrenal medulla
Norepinephrine and
epinephrine secreted
Bladder
Wall relaxed
Sphincter closed
Wall contracted
Sphincter relaxed
Structure Sympathetic Stimulation Parasympathetic Stimulation
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

23. Sympathetic Division
‘Thoracolumbar’

24. The Sympathetic Division
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy

25. The Sympathetic Ganglion
• Paravertebral ganglion
– Located parallel to spinal cord on either
side
– Connected to the spinal nerve through
the grey and white rami
• Prevertebral Gangliaon
– Lie anterior to the vertebral column
– Occur only in abdomen and pelvis
– Unpaired, not segmentally arranged
– Also called collateral
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

26. Postganglionic Neurons
3 types of postganglionic fibres
– Which enter the spinal nerve through
the grey ramus
– Which travel along the blood vessels to
supply head & neck
– From collateral ganglia which travel
short distance to innervate visceral
organs
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

27. The Sympathetic Ganglion

28. Sympathetic Pathways to the Head
Figure 15.10

29. Sympathetic Pathways to Thoracic Organs
Figure 15.11

30. Sympathetic Pathways to Periphery
Figure 15.9

31. The Adrenal Medulla
Figure 15.14

32. Parasympathetic Division
‘Craniosacral’

33. The Parasympathetic Division
• Preganglionic neurons originate in the
brainstem and the lateral horn of the spinal
cord in sacral region
• Pass through cranial nerves III, VII, IX, X and S2-
4
• Extend some distance, synapse in terminal
ganglia, and release Ach
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

34. • Postganglionic neurons originate in the terminal ganglia, pass a short distance and then
release Ach

35. Parasympathetic innervations

36. Cranial Outflow
Nerve
Origin of
preganglionic
fibers
Location of
terminal ganglia
Effector organ
Occulomotor nerve
(III) nerve
Midbrain Cilliary ganglion
Eyes (smooth
muscle in iris &
cilliary body )
Facial (VII) nerve Pons
Pterygopalatine &
submandibular
ganglia
Lacrimal, Salivary
& mucous glands
Glossopharyngeal
(IX) nerve
Medulla oblongata Otic ganglion Parotid gland
Vagus (X) nerve Medulla oblongata Terminal ganglia
Heart, lungs, GI
tract, liver,
pancreas

38. Sacral Outflow
• Emerges from S2-S4
• Form splanchnic nerves
• Innervates lower half of large intestine,
rectum, urinary bladder, reproductive organs
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

39. ANS Dual Innervations
• The Sympathetic and
Parasympathetic -- Divisions of the
ANS innervate many of the same
organs
-Different effects are due to specific
different neurotransmitters and
receptor types of effectors
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

40. ANS Dual Innervations

41. Neural Communication
 Neurotransmitters
 Chemical messengers that traverse the
synaptic gaps between neurons
 When released by the sending neuron,
neurotransmitters travel across the
synapse and bind to receptor sites on the
receiving neuron, and thereby bring
about effect
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

42. Neurotransmitters
ACh ACh
Sweat
glands
Striated
muscle
ACh
SOMATIC NERVOUS SYSTEM
Heart
Sm. mus.
Glands
ACh ACh
Parasympathetic
ACh E,
NE
Ad. M.  
Heart
Sm. mus.
Glands
ACh NE
AUTONOMIC NERVOUS SYSTEM
Sympathetic

43. Neurotransmitters
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy Blvd., Suite 1800
Philadelphia.

44. Adrenergic receptors
• α1 - smooth muscles, blood
vessels, glands & gut
• α2 - nerve endings, β cells
• β1 - heart, JG cells
• β2 - bronchi, blood vessels, liver
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

45. NEpi α1
Epi β1
β2
Generally excitatory effect on
cell, except at GI smooth
muscle
Excitatory effect on cardiac
muscle cells
Generally very powerful
inhibitory effect on cell
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee brothers medical publishers,Delhi

46. Cholinergic receptors
• Muscarinic – heart, blood
vessels, eye, smooth
muscles, GI glands
• Nicotinic – skeletal muscles,
end plate of ganglionic cells
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

47. Pharmacology
Neurotransmitters of the
Autonomic Nervous System

48. Adrenergic agents/ ,44
• Adrenaline
– Anaphylaxis
• Physiologic antagonist of histamine
• Reverse vasodilatation & bronchospasm
brought about by histamine
• Act on β2 & α1 receptors
– Hypotension
– Bronchial asthma
• Act on β2 receptor & cause
bronchodilatation
– Cardiac arrest
• Act on β1 receptor to stimulate heart
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

49. • Dopamine
– Useful in cardiogenic shock to ↑ supply to
renal tissues as D1 receptors in renal and
mesentric blood vessels are most sensitive
– Increases g.f.r
– Used in patients with cardiogenic/septic
shock and severe CHF- increases B.P and
urinary blood flow
Adrenergic agents/Sympathomimetics
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

50. Adrenergic antagonists/Sympatholytics
• α blockers
– Prazosine- in hypertension
• β blockers
– Atenolol-
• its cardioselective β blocker
• Hypertension, Angina pectoris, MI,
arrhythmia
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

51. Cholinergic drugs/Parasympathomimetics
• Pilocarpine
– Mainly muscarinic actions
– ↑ secretions, salivation, miosis
• Anticholinesterase
– Neostigmine
• Mainly nicotinic action
• Reverses muscle paralysis after anesthesia
• Post op paralytic ileus/ urinary retention
• In snake bite along with atropine to
prevent respiratory paralysis
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

52. Anticholinergic drugs/ Parasympatholytics
• Atropine
– Blocks mainly muscarinic actions
– Preanesthetic medication
• ↓ secretions
• Muscle relaxant
– Cardiac vagolytic
• Helps in counteracting bradycadia and
partial heart block→ ↑heart rate
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee
brothers medical publishers,Delhi

53. Applied Aspects

54. Horner’s syndrome
• Ptosis
• Miosis
• Anhydrosis
Maloney WF, Younge BR, Moyer N. Evaluation of the causes and accuracy of pharmacologic
localization in Horner syndrome. Am J Ophthalmol 1980;90:394-402.

55. Frey Syndrome
• Auriculotemporal syndrome or gustatory
sweating and flushing results from nerve
injury, usually post-surgical or post-
infection.
• This nerve carries parasympathetic fibers to
the parotid and sympathetic vasomotor
fibers to the preauricular skin.
• 5% resolve; if needed, possible treatment
ranges from atropine or botox injections,
scopolamine cream or severing the nerve.
Linder TE, Huber A, Schmid S. Frey’s syndrome after parotidectomy:a
retrospective and prospective analysis. Laryngoscope1997;107(11):1496-501.

56. Frey Syndrome
Linder TE, Huber A, Schmid S. Frey’s syndrome after parotidectomy:a retrospective and prospective analysis.

57. Myasthenia Gravis
• 1 in 10,000 population.
• Antibodies directed against nicotinic
receptors.
• Weakness and easy fatigability on repeated
activity, with recovery after rest.
• Neostigmine 15mg QID .
• Pridnisolone 30-60mg/day.
(inhibits production of antibodies)
K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee brothers medical publishers,Delhi

58. Raynaud’s Disease
• Severe vasoconstriction of the blood supply to
the fingers, toes and occasionally the ears and
nose
• During a Raynaud’s attack, skin color changes
(pallor, cyanosis, rubor) which are often
accompanied by a throbbing or burning
sensation, cold, and numbness occur
• Ischemia can be so extreme as to cause gangrene
Landry GJ:Current medical and surgical management of Raynaud’s syndrome.
JVascSurg57:1710-1716,2013

59. SHOCK
COMPENSATORY MECHANISM
Sympathetic Nervous System (SNS)-Adrenal
Response
• SNS - Neurohormonal
response Stimulated by
baroreceptors
• Increased heart rate
• Increased contractility
• Increased Preload
• Vasoconstriction
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.

60. • SNS - Renin-angiotensin system
Decrease renal perfusion Releases renin
angiotensin I angiotensin II
((potent vasoconstriction)
releases aldosterone adrenal cortex
sodium & water retention
increased blood volume and pressure
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

61. • SNS - Hormonal: Antidiuretic Hormone
Osmoreceptors in hypothalamus stimulated
ADH released by Posterior pituitary gland
• Vasopressor effect to increase BP
• Acts on renal tubules to retain water
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

62. Referred pain
• Referred pain is a phenomenon in
which pain originating in one part of
the body is felt as though it
originated in another part of the
body.
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006;
Elsevier Inc.1600 John F. Kennedy Blvd., Suite 1800 Philadelphia.
Eg. afferents from the heart enter the
spinal cord at the same level as those from
the shoulder region. This is why pain in the
heart (a heart attack) is often referred to
the shoulder.
The sympathetic afferents mainly carry
information about visceral pain. Since this
information converges with pain from the
body surface, the pain is often perceived
as originating at the body surface instead
of deep in the viscera.

63. Role of ANS in Post-surgical Patients
• Post – operative arrythmia and
hypertension
Operative stress causes sympathetic overactivity
which stimulates the heart to maintain high rate
and pressure
Post – operative urine retention
It is normal for a patient to have reduced
urine output for 24 hrs post – operatively
due to the overactive sympathetic system.
Care should be taken if this extends for a
longer period
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier
Inc.1600 John F. Kennedy Blvd., Suite 1800 Philadelphia.

64. Use of ANS in lie detector
Lie detectors work by recording changes in heart rate, or in the
sweatiness of palms - both of these increase when someone is telling
a lie

65. Studying ANS helps to understand the body responses to
stressful conditions like trauma, infection and surgery.
Conclusion
Further research about the receptors, neurotransmitters and
the agents acting on them can aid in better control over the
various body responses in stress and at rest.
Closely monitored medication can be use to control the
neurotransmitters to alleviate symptoms that may be
associated with diseases.
Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600 John F. Kennedy
Blvd., Suite 1800 Philadelphia.

66. 1. K D Tripathi, Essentials of Medical Pharmacology,6th edition,2008 Jaypee brothers medical
publishers,Delhi
2. Taylor EW, Jordan D, Coote JH: Central control of the cardiovascular and respiratory systems
and their interactions in vertebrates. Physiol Rev 79:855, 1999.
3. Guyton and Hall , Textbook Of Medical Physiology, 11th edition; 2006; Elsevier Inc.1600
John F. Kennedy Blvd., Suite 1800 Philadelphia.
4. Maloney WF, Younge BR, Moyer N. Evaluation of the causes and accuracy of pharmacologic localization
in Horner syndrome. Am J Ophthalmol 1980;90:394-402.
5. Linder TE, Huber A, Schmid S. Frey’s syndrome after parotidectomy: a retrospective and
prospective analysis. Laryngoscope1997;107(11):1496-501.
6. Landry GJ:Current medical and surgical management of Raynaud’s syndrome.
JVascSurg57:1710-1716,2013
References

67. Thank You…