The autonomic nervous system (ANS) controls involuntary bodily functions and is divided into the sympathetic and parasympathetic nervous systems. The sympathetic system prepares the body for "fight or flight" through increased heart rate, breathing, and metabolism. The parasympathetic system acts to conserve energy and promote rest through decreased heart rate and increased digestion. The ANS regulates organ systems like the heart, lungs, and digestive system through both divisions to maintain homeostasis.

1. AUTONOMIC
NERVOUS
SYSTEM
Presented by,
Vipin Chandran
17-Mar-21 1

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. Enteric nervous system
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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
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4. ● The autonomic nervous system (ANS) regulates the
activities of cardiac muscle, smooth muscle, and
glands.
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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
Counter balances sympathetic function
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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
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9. Comparison Somatic and
Autonomic Nervous
System
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10. Characteristics
1.Sensory
neuron
2.Effector
3.Control of
motor neuron
Somatic nervous
system
Somatic senses and
special senses
Skeletal muscle
Voluntary control
Autonomic nervous
system
Mainly from interoceptors
located in blood vessel,
visceral organ, nervous
system that monitor
internal environment)
Cardiac, smooth muscle
and glands
Involuntary control
Comparison Somatic and
Autonomic Nervous System
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11. Characteristics Autonomic nervous
4. Motor neuron
(efferent) pathway
Somatic nervous
system
One motor axon
from CNS to effector
system
Two neuron pathway:
One motor axon from
CNS to autonomic
ganglion
(preganglionic)
One motor axon from
autonomic ganglion to
effector
(postganglionic)
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14. 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.
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15. ●Cardiovascular System
●Increasing heart beat
●Increase blood supply to cardiac muscle (dilate the
coronary artery)
●Constrict the blood vessel in secretory glands of
digestive system
●Accelerates blood coagulation because of
vasoconstriction.
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16. ●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.
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17. ●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.
●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
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18. ●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.
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19. ●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
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20. ● 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.
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21. 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.
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