Physiology of Autonomic Nervous System

1. Autonomic Nervous System
Prof. Dr. Rashid Mahmood

2. 6-Jan-18 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 2
Autonomic Nervous
System
• Importance:
 Controls of all visceral
functions of body
 Pharmacology
 Medicine
 Examination

3. Objectives
Goal/Aim: To give the understanding of the physiology
of Autonomic Nervous System (ANS)
• To describe the physiologic anatomy of Sympathetic and
Parasympathetic nervous system.
• To classify the receptors of ANS, and relate them with the
functions of ANS
• To describe the functions of Sympathetic and
Parasympathetic nervous system.
• To list the neurotransmitters secreted at the at nerve
endings of ANS.
• To list the components of Visceral reflex Arc and give
examples.
• To tell the correlation of adrenal medulla with ANS6-Jan-18 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 3

4. Control of body functions
•Nervous system
•Hormones
Skeletal muscles
Visceral functions
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5. MCQ 1
1. Regarding Autonomic outflow and
Autonomic nerve fibers
A. Sympathetic outflow is from T-1 to S-3.
B. In the parasympathetic nervous system the axons of
postganglionic neurons are usually longer than those of
preganglionic neurons
C. In case of sympathetic nervous system all the
preganglionic nerves synapse in the sympathetic chain
ganglia.
D. Sympathetic nervous system is part of afferent division of
the peripheral nervous system
E. Sympathetic fibers leave the spinal nerve through White
Ramus Communicans to enter the sympathetic chain
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6. Organization of
Nervous System
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7. Autonomic Nervous System
•Visceral functions
•Heart
•GIT
•Urinary Bladder
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8. Preganglionic and postganglionic neurotransmitter
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9. Visceral Reflexes
Components of
Visceral Reflex
1 2
3
4
567
Ganglion on
the way of
efferent nerve
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10. Autonomic Nervous System
•Higher control:
•Spinal cord
•Brain Stem
•Hypothalamus
•Limbic System
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11. Divisions of Autonomic nervous system
•Sympathetic nervous system
•Parasympathetic nervous system
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12. Sympathetic Division
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Notes: 4 possible routes of
sympathetic nerve after entering
corresponding sympathetic chain
ganglion (paravertebral ganglion):
1. synapse & come out at the
same level in Grey RC to
accompany corresponding spinal
nerve
2. Come out without synapse &
synapse in collateral (prevertebral)
ganglion outside sympathetic
chain ganglion
3. Go up inside sympathetic chain
& synapse in cervical ganglia
before coming out
4. Go down inside sympathetic
chain & synapse below L2 before
coming out
Spinal cord
Ventral horn
Spinal nerve
Leave spinal N.
thru White RC
Sympathetic
chain

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Sympathetic
Division

14. Parasympathetic Division
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15. Organization of
Autonomic NS
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16. MCQ 1
1. Regarding Autonomic outflow and
Autonomic nerve fibers
A. Sympathetic outflow is from T-1 to S-3.
B. In the parasympathetic nervous system the axons of
postganglionic neurons are usually longer than those
of preganglionic neurons
C. In case of sympathetic nervous system all the
preganglionic nerves synapse in the sympathetic chain
ganglia.
D. Sympathetic nervous system is part of afferent division
of the peripheral nervous system
E. Sympathetic fibers leave the spinal nerve through
White Ramus Communicans to enter the sympathetic
chain
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17. MCQ 2
Regarding Neurotransmitters and Characteristics of Autonomic Nervous System
A. Acetylcholinesterase is the chemical transmitter at the neuromuscular junction.
B. Noradrenalin is chemical transmitter at all neuromuscular junctions in autonomic
nervous system
C. GnRH (Gonadotrophin Releasing Hormone) is a hormone, not a neurotransmitter
D. The characteristic of the autonomic nervous system is that it exerts either
excitatory or inhibitory effect on its Effector organs
E. Sympathetic nervous system is always excitatory
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18. Basic Characteristics
Cholinergic
&
Adrenergic (Noradrenergic) Fibers

19. Sympathetic Parasympathetic
Cholinergic Cholinergic
Cholinergic
Adrenergic
Cholinergic
Sweat Glands, Piloerecror Muscle,
A few Blood Vessels
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22. MCQ 2
Regarding Neurotransmitters and Characteristics of Autonomic Nervous System
A. Acetylcholinesterase is the chemical transmitter at the neuromuscular junction.
B. Noradrenalin is chemical transmitter at all neuromuscular junctions in autonomic
nervous system
C. GnRH (Gonadotrophin Releasing Hormone) is a hormone, not a neurotransmitter
D. The characteristic of the autonomic nervous system is that it exerts either
excitatory or inhibitory effect on its Effector organs
E. Sympathetic nervous system is always excitatory
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D

23. MCQ 3
Which of the following statements is NOT TRUE
concerning the Autonomic Nervous system
A. Nicotinic receptors are a type of cholinergic
receptors
B. Sacral outflow of parasympathetic nervous
system is from S-2 to S-4
C. Parasympathetic nerve fibers have a ganglion
close to or in the organ which they innervate
D. Limbic system is involved in the control of
Autonomic Nervous System
E. Acetylcholine is the chemical transmitter at all
neuromuscular junctions in autonomic nervous
system
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24. Receptors
Cholinergic
Muscarinic Nicotinic
Adrenergic
Alpha
Alpha 1 Alpha 2
Beta
Beta 3
Beta 1 Beta 2
Autonomic receptors

25. N1
N2N2
N2
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26. Adrenergic
Receptors6-Jan-18 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 26

27. Function of the autonomic nerves
is determined by the type of
receptor
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General outlay of ANS
Sherwood

29. Autonomic receptors
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Receptor Type Neurotransmitter
Affinity
Effector(s) with
Receptor Type
Effect on Effector
Cholinergic
Nicotinic
ACh from autonomic
preganglionic fibers
All autonomic
postganglionic cell
bodies; adrenal
medulla
Excitatory
ACh from motor
neurons
Motor end plates of
skeletal muscle fibers
Excitatory
Muscarinic
Ach from
parasympathetic
postganglionic fibers
Cardiac muscle,
smooth muscle,
glands
Excitatory or
inhibitory, depending
on effector
Adrenergic
α1
Greater affinity for
NE than for E
Most sympathetic
target tissues
Excitatory
α2
Grater affinity for NE
than for E
Digestive organs Inhibitory
β1
Equal affinity for NE
and for E
Heart, Kidney (Renin
release), Fat cells
Excitatory
β2
Affinity for E only Arterioles, Uterus,
UB, intestines,
bronchioles
Inhibitory
3
4
5
6
7
8
9
10
11
12
13 14 15
16 17 18
19 20 21
22
23 24

30. MCQ 3
Which of the following statements is NOT TRUE
concerning the Autonomic Nervous system
A. Nicotinic receptors are a type of cholinergic
receptors
B. Sacral outflow of parasympathetic nervous
system is from S-2 to S-4
C. Parasympathetic nerve fibers have a ganglion
close to or in the organ which they innervate
D. Limbic system is involved in the control of
Autonomic Nervous System
E. Acetylcholine is the chemical transmitter at all
neuromuscular junctions in autonomic nervous
system
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31. Autonomic Functions
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32. Sympathetic functions
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33. Parasympathetic functions
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34. Autonomic functions
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35. Autonomic functions
Organ Parasympathetic Sympathetic
EYE 1. Miosis
2. Near Accommodation
1. Mydriasis(α
receptors)
2. Opposite
HEART 1. ↓ Heart rate
2. ↓ force of contraction
3. ↓ Conduction of velocity
Opposite
(ß-1 receptors)
BLOOD
VESSELS
1. Dilation ? 1. Alpha receptors:
Constriction
2. ß-2 receptors :
Dilatation e.g.
Coronary
arteries, skeletal
muscles

36. Organ Parasympathetic Sympathetic
Lungs 1. Muscle contraction
2. ↑ secretion
Opposite(ß-2)
GIT Stomach, Intestine
1. ↑ Motility
2. ↑ Secretions
3. Sphincters relaxed
Gall Bladder/Ducts:
Contraction
Opposite
URINARY
BLADDER
1. Muscle Contraction
2. Sphincter relaxed
Opposite
MTABOLISM 1. Anabolism Catabolism (ß
receptors)
• ↑ glycogenolysis
• ↑ lipolysis
• ↑ BMR

37. Organ Parasympathetic Sympathetic
Kidney Nil ↑ Renin
Mental
activity
Nil ↑
Skeletal
Muscle
Nil ↑ Glycogenolysis
↑ Stretch

38. Autonomic Functions
•Opposite
•Excitatory/Inhibitory (Exception: Salivary Glands)
•Parasympathetic:
•Localized
•Sympathetic:
•Diffuse
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39. 39
Function of Adrenal Medulla
• Catecholamines
• Epinephrine (Adrenaline): 80%
• Norepinephrine (Noradrenalin): 20%
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40. Self-Study Topics
1. Value of dual autonomic supply
2. Denervation Hypersensitivy
3. Autonomic control areas in brain stem and hypothalamus
4. Sympathetic and parasympathetic tone
5. Mass discharge vs. Localized response “Alarm” or “stress”
response
6. Autonomic reflexes
7. frequency of stimulation required for full activation
8. Differences between functions of epinephrine and
norepinephrine 406-Jan-18 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood

41. EOLA
1. Which of the types of autonomic fibers release acetylcholine (Ach)?
2. Would a drug that interferes with Ach action at nicotinic receptors block the
influence of the parasympathetic nervous system, the sympathetic nervous
system, or both, at effector organs? How about for a drug that interferes with
Ach action at muscarinic receptors?
3. Name some organs that are innervated only by sympathetic nerves and not by
the parasympathetic nerves
4. In which organs actions of sympathetic and parasympathetic activity are not
antagonistic?
Answers:
1.All preganglionic , parasympathetic postganglionic, a few postganglionic
sympathetic e.g Sweat glands
2.Both, It will block only parasympathetic actions
3.Blood vessels (most arterioles and veins), Sweat glands
4.Salivary glands
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Feedback

42. Thank You
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