This ppt will give u the understanding about the principle of Autonomic Nervous System

1. CHAPTER 3CHAPTER 3
AUTONOMIC NERVOUS SYSTEMAUTONOMIC NERVOUS SYSTEM
By Hermizan Bin HalihanafiahBy Hermizan Bin Halihanafiah
hermizanhalihanafiah@gmail.comhermizanhalihanafiah@gmail.com

2. INTRODUCTION
 The peripheral nervous system, or PNS,
consists of the cranial nerves, spinal nerves
and ganglia.
 The peripheral nervous system subdivided
into:
1. Autonomic nervous system:
- sympathetic nervous system
- parasympathetic nervous system
2. Somatic nervous system

3. The autonomic nervous system (ANS or visceral nervous
system) is the part of the peripheral nervous system that acts
as a control system functioning largely below the level of
consciousness, and controls function.
Responsible for control of “involuntary” or visceral bodily
function:
 Cardiovascular
 Respiratory
 Digestive
 Urinary
 Reproductive functions
 Key role in the bodies response to stress
AUTONOMIC NERVOUS SYSTEM

4. General function of the
autonomic nervous system.
 The autonomic nervous system (ANS) regulates the
activities of cardiac muscle, smooth muscle, and
glands.

5. It is classically divided into two subsystems:
SYMPATHETIC NERVOUS SYSTEM:
Allow body to function under stress
Fight or flight
Primes body for intense skeletal muscle activity
PARASYMPATHETIC NERVOUS SYSTEM
Maintenance functions
Rest-and-digest
Counterbalances sympathetic function
AUTONOMIC NERVOUS SYSTEM

6. “Fight or flight”Sympathetic
Parasympathetic “Rest and Digest”

8.  In general nerve impulses from one division of the
ANS stimulate the organ to increase its activity
(excitation), and another part inhibit the organs
activity (inhibition).
 Structurally, ANS includes:
a. autonomic sensory neurons (afferent)
b. integrating centers in the CNS
c. autonomic motor neurons (efferent)
AUTONOMIC NERVOUS SYSTEM

9. Comparison Somatic and
Autonomic Nervous System

11. Characteristics Somatic nervous
system
Autonomic nervous
system
Sensory neuron Somatic senses and
special senses
Mainly from interoceptors
9located in blood vessel,
visceral organ, nervous
system that monitor
internal environment)
Effector Skeletal muscle Cardiac, smooth muscle
and glands
Control of motor
neuron
Voluntary control
from cerebral cortex,
with contribution
from basal ganglia,
cerebellum,
brainstem and spinal
cord.
Involuntary control from
hypothalamus, lymbic
system, brain stem and
spinal cord; limited
control from cerebral
cortex.
Comparison Somatic and
Autonomic Nervous System

12. Characteristics Somatic nervous
system
Autonomic nervous
system
Motor neuron
(efferent) pathway
One motor axon
from CNS to effector
Two neuron pathway:
One motor axon from
CNS to autonomic
ganglion
(preganglionic)
One motor axon from
autonomic ganglion
to effector
(postganglionic)

13. Characteristics Somatic nervous
system
Autonomic nervous
system
Location of
ganglion
Motor in CNS.
Sensory in dorsal
root.
Autonomic ganglion
outside CNS.
Preganglionic and sensory
shared with somatic
nervous system.
Neurontransmitter Acetylcholine (Ach):
always excitatory
Sympathetic
postganglionic neurons
release Norepinephrine
(NE), to sweat gland
release ACH. All
parasympathetic
postganglionic neurons
release ACh.

19. ANATOMY OF
AUTONOMIC MOTOR PATHWAYS

20. OVERVIEW
a. PREGANGLIONIC NEURONS (type B)
b. AUTONOMIC GANGLIA
c. POSTGANGLIONIC NEURONS (type C)
ANATOMY OF
AUTONOMIC MOTOR PATHWAYS

21. a. Preganglionic neurons:
Its cell body located within gray matter of the CNS
(brain or spinal cord)
Its myelinated axon exits the CNS.
The preganglionic axon passes from the CNS in a spinal
or a cranial nerve.
The preganglionic axon terminates in a ganglion.
b. Autonomic ganglion.
A ganglion is a collection of nerve cell bodies located in
a specific site within the body, but outside the CNS.

22. c. Postganglionic neurons:
The cell body located in an autonomic ganglion.
The location of the ganglion is dependent upon the
division of the ANS to which the neuron belongs and
which organ it will innervate.
The axons of a postganglionic unmylinated fiber.
The postganglionic axon passes from the ganglion to
the effector (cardiac muscle, smooth muscle, or
gland) is either stimulated or inhibited.

26. Sympathetic Preganglionic Neurons
In the Sympathetic Division (thoracolumbar division):
The cell bodies in the lateral horns of the gray
matter in the 12 thoracic segments (T1-T12) and
the first two (L1-L2) lumbar segments of the spinal
cord. Therefore, the sympathetic division is called
the thoracolumbar division.
Their axons travel in the spinal nerves of these
segments, known as the thoracolumbar outflow.

29. Parasympathetic Preganglionic Neurons
In the Parasympathetic Division (craniosacral
division)
cell bodies arise from the nuclei of cranial nerves in
the brainstem III, VII, IX, and X and in the lateral
gray matter of the second through fourth sacral
segments (S2-S4) of the spinal cord, called the
craniosacral division.
 The axons of the preganglionic neurons are
referred to as the craniosacral outflow.

33. AUTONOMIC GANGLIA
Two major groups of autonomic ganglia:
1. Sympathetic ganglia (sympathetic division)
i. Sympathetic trunk ganglia (vertebral chain
ganglia or paravertebral ganglia)
ii. Prevertebral ganglia
2. Parasympathetic ganglia (pasympathetic
division)
i. Terminal ganglia (ciliary ganglion,
pterygopalatine ganglion, submandibular
ganglion, otic ganglion)

35. i. Sympathetic trunk ganglia (Vertebral chain
ganglia or paravertebral ganglia)
 Lie in a vertical row on either side of the vertebrae
column.
 Extend from the base of the skull to the coccyx.
 Postganglionic axons from sympathetic trunk
ganglia primarily innervate organs above the
diaphragm.
 In the neck (specific names) called superior
cervical ganglion, middle cervical ganglion,
and inferior cervical ganglia.
 Most sympathetic preganglionic axons are shorter
than sympathetic postganglionic axons because
sympathetic trunk ganglia near to the spinal cord.
Sympathetic ganglia

37. ii. Prevertebral ganglia in the sympathetic
division:
 Lie anterior to the vertebral column and close to
the large abdominal arteries.
 In general, postganglionic axons from
prevertebral ganglia innervate organs below to
the diaphragm.
 5 major prevertebral ganglia:
i) Celiac ganglion
ii) Superior mesenteric ganglion
iii) Inferior mesenteric ganglion
iv) Aorticorenal ganglion
v) Renal ganglion
Sympathetic ganglia

38. Celiac ganglion – on either side of the celiac
trunk, an artery that just inferior to the
diaphragm.
Superior mesenteric ganglion – near the
beginning of the superior mesenteric artery in the
upper abdomen.
Inferior mesenteric ganglion – near to the
inferior mesenteric artery in the middle of the
abdomen.
Aorticorenal ganglion and renal ganglion –
near to the renal artery of each kidney.

41. Sympathetic trunk
ganglia /
paravertebral ganglion
Prevertebral ganglion

42. Parasympathetic Ganglia
Terminal ganglia - The parasympathetic division
uses terminal (intramural) ganglia located very close to
or within the walls of a viscera organ to be innervated.
Terminal ganglia in the head are the ciliary
ganglion, pterygopalatine ganglion,
submandibular ganglion and otic ganglion.
Parasympathetic preganglionic axons are longer
than parasymapthetic postganglionic axons
because terminal ganglia are close to the visceral
organ.

44. Postganglionic Neurons
Because of the locations of ganglia, sympathetic
postganglionic fibers are relatively long while
parasympathetic postganglionic fibers are relatively short.

45. IN THE SYMPATHETIC DIVISION
Once axons of sympathetic preganglionic neurons
pass to sympathetic trunk ganglia, they may
connect with postganglionic neurons in one of the
following ways:
1. An axons may synapse with postganglionic neurons in
the ganglion it first reaches.
2. An axons may ascend or descend to a higher or lower
ganglion before synapsing with postganglionic neurons.
The network of incoming axons collectively called
sympathetic chains.
Sympathetic Postganglionic Neurons

46. 3. Without synapsing, an axons continue through
the sympathetic trunk ganglion to end at
prevertebral ganglion and synapse with
postganglionic neurons there.
4. Without synapsing, an axons may pass through
sympathetic trunk ganglion and prevertebral
ganglion and extend to the chromaffin cells of
adrenal medulla.
Sympathetic
Postganglionic Neurons

47. A single sympathetic preganglionic fiber has
many axon collateral.
This explain why many sympathetic responses
affect almost the entire body simultaneously.
After exiting to their ganglia, the postganglionic
axons typically terminate in several visceral
effector.
Sympathetic
Postganglionic Neurons

48. SYMPATHETIC DIVISION

49. IN THE PARASYMPATHETIC DIVISION
Axons of preganglionic neurons of the
parasympathetic division pass to the terminal
ganglia near or within a visceral effector.
In the ganglion, the presynaptic neuron usually
synapse with 4 or 5 postsynaptic neurons, all of
which supply a single visceral effector, allowing
parasympathetic response to be localized to a
single effector.
Postganglionic Neurons

51. EFFECTS OF SYMPATHETIC
NERVOUS SYSTEM
The sympathetic system prepares the body to meet
emergency demands and is primarily involved with
processes that expend energy. During physical or
emotional stress, the sympathetic division dominates
the parasympathetic system, initiating a series of
activities known as the fight-or-flight response.
In addition, there is activation of the adrenal medulla,
causing secretion of norepinephrine and epinephrine as
hormones to greatly heighten the response.

52. Cardiovascular System
Increasing heart beat
Increase blood supply to cardiac muscle (dilate
the coronary artery)
Raised peripheral resistance and blood pressure
by constricting the small artery the skin. In this
way increase blood supply is available for highly
active tissue, such as skeletal muscle, heart and
brain.
Constrict the blood vessel in secretory glands of
digestive system
Accelerates blood coagulation because of
vasoconstriction.

53. Respiratory system
Causes smooth muscle relaxation and therefore
dilatation of the airways, especially bronchioles.
Allowing a greater amount of air to enter the
lungs at each inspiration, and increase the
respiratory rate.
Deal with ’fight and flight’ situation.

54. Digestive and urinary system
Liver increase conversion of glycogen to glucose
Stomach and small intestine; smooth muscle
contraction (peristalsis) and secretion of digestive
juices are inhibited, delaying digestion and the
tone of sphinxter muscle is increased.
Adrenal gland; stimulated to secrete adrenaline and
noradrenaline which potentiate and sustain the
effect of sympathetic stimulation
Urethral and anal sphincter; muscle tone increase,
inhibit micturition and defecation.
Bladder walls relaxes
Metabolic rate increase

55. Eye
Dilating the pupil
Opening the eyes open wide and giving the
appearance of alertness and excitement
Skin
Increase sweat secretion, leading to increased
heat loss from the body
Contract the arrector pili muscle on the skin
Constrict the peripheral blood vessel increasing
blood supply available to active organs, e.g
heart and skeletal muscle.

56. The parasympathetic nervous system is an energy
conservation-restorative system. It regulates those
activities that conserve and restore body energy
during times of rest and digest.
The parasympathetic nervous system dominates over
sympathetic activity in the glands and smooth muscle
of the gut, stimulating glandular secretion and the gut
movements necessary for food to be digested and
absorbed.
Salivation, lacrimation, urination, and defecation, all
controlled by the parasympathetic nervous system.
EFFECTS OF PARASYMPATHETIC
NERVOUS SYSTEM

57.  Cardiovascular System
Decrease the rate and force of the heartbeat
Constrict the coronary artery reducing the
blood supply to cardiac muscle
Respiratory
Produces contraction of smooth muscle in
airway walls causing their constriction, e.g.
bronchioles and bronchi
Eye
Constricting the pupil
The eyelids tend to closed, giving the
appearance of sleepiness.

58. Digestive and urinary system
Liver: conversion of glucose to glycogen and
secretion of bile are increased.
Stomach and small intestine: Motility and
secretion are increased together with the rate of
digestion and absorption of food.
Pancreas: secretion of pancreatic juice and the
hormone insulin are increase.
Urethral and anal sphincter: relaxation in
urethral and anal sphincter, micturition and
defecation occurs.

63. Neurotransmitters are chemicals which transmit
signals from a neuron to a target cell across the
synapes.
The postganglionic neurons use different
neurotransmitters and the effectors bear different
receptors.
The hypothalamus regulates the balance of
sympathetic versus parasympathetic activity or tone.
 In general, we are in parasympathetic tone, except
during states of emergency when we immediately
switch to sympathetic tone.
Neurotransmitter
(Autonomic Nervous system)

64. At a sympathetic nervous system:
Preganglionic neurons use Acetylcholine
(ACh) as a neurotransmitter.
Most postganglionic neurons utilize
noradrenaline (norepinephrine)—with the major
exception that postganglionic neurons
innervating sweat glands use acetylcholine.

66. At the parasympathetic nervous system:
all preganglionic neurons and all postganglionic
parasympathetic neurons uses Acetylcholine
(ACh) as its neurotransmitter

68. NEUROTRANSMITTER