PNS, cranial nerves spinal nerves

1. PERIPHERAL NERVOUS SYSTEM
BY
SONI KUMARI SHAH

2. PNS
The PNS consists of nerves and ganglia outside the brain and spinal cord.
The main function of PNS is to connect CNS to the limbs and organs,
essentially serving as relay station between brain & spinal cord and rest of
the body.
PNS consists of:
12 pairs of cranial nerves
31 pairs of spinal nerves

3. Cranial Nerves
12 pairs of nerves that arises from the brain are cranial nerves
Name Nerve Type Function
I Olfactory Sensory Smell
II Optic Sensory Vision
III Oculomotor Motor Movement of eye
IV Trochlear Motor Moves eye
V Trigeminal Both Face sensation. Mastication
VI Abducent Motor Abducts the eye
VII Facial Both Facial expression, taste
VIII Vestibulocohlear Sensory Hearing, balance
IX Glossopharyngeal Both Taste, gag reflex
X Vagus Both Gag reflex, parasympathetic innervation
XI Accessory Motor Shoulder shrug
XII Hypoglossal Motor Swallowing, speech

4. Cranial Nerves
Some Say Marry Money But My Brother Says Bad
Boys Marry Money
Ohh Ohh Ohh To Touch And Feel Very Good Velvet.
Such Heaven!

5. Spinal Nerves
31 pairs of spinal nerves arises from the spinal cord
8 pairs cervical nerves
12 pairs thoracic nerves
5 pairs lumbar nerves
5 pairs sacral nerves
1 pair coccygeal nerves
Parts of spinal nerves
1. Root: Dorsal Root
Ventral Root
2. Trunk
3. Ramus And Branches: Dorsal Ramus
Ventral Ramus

6. Spinal Nerve Plexuses
S. N. Nerve Root Plexus Plexus supply to
1
C1-C4
C3-C5=Phrenic
Cervical Scalp & neck, diaphragm
2 C5-T1 Brachial Arm
3 T2-T11 No plexus formed Intercostal nerves serve chest wall
4 T12-L4 Lumbar Abdominal wall, antero-medial thigh
5 L5-S1 sacral Posterior thigh, lower leg and foot

7. Autonomic Nervous System
The autonomic or involuntary part of the nervous system controls
involuntary body functions.
The autonomic nervous system is separated into two divisions:
• sympathetic (thoracolumbar outflow)
• parasympathetic (craniosacral outflow).

8. Sympathetic Nervous System
Originates in spinal cord and functions to activate the physiological changes
in fight, flight or fright.
Utilizes and activates the release of norerpnephrine in reaction.
Parasympathetic Nervous System
Originates in spinal cord and medulla and works with sympathetic nervous
system.
Functions to activate rest and digest response and return the body to
homeostasis after fight or flight reaction.
Utilizes and activates the release of acetylcholine.

9. Differences Between Sympathetic And Parasympathetic Nervous System
S.N Sympathetic Nervous System Parasympathetic Nervous System
1 It is thoracolumbar in origin i.e originates from T1-L2 It is craniosacral in origin i.e originates from brainstem to S2, S3, S4
2 Ganglia are located in pre and paravertebral region. Ganglia are located in effector organ.
3 Preganglionic fibers are shorter & postganglionic
fibers are longer.
Preganglionic fibers are longer & postganglionic fibers are shorter.
4 Distribution of postganglionic fibers is wide. Distribution of postganglionic fibers is limited.
5 Its nerve ending are adrenergic in nature. Its nerve ending are cholinergic in nature.
6 It is active during fight, flight and fright. It is active during rest.
7 It dilates pupil. It constricts pupil.
8 It increases sweat production. No PS effect.
9 It increases heart rate. It decreases heart rate.
10 It dilates respiratory airways. It constricts respiratory airways.
11 It decreases secretion of saliva It increases secretion of saliva
12 It decreases peristalsis. It increases peristalsis.
13 It inhibits contraction of bladder wall. It stimulates contraction of bladder wall.

10. Pure sensory cranial nerves are
1. III, IV,V
2. I, II, III
3. I, II, VIII
4. II, III. VII
Glossopharyngeal is one of cranial nerve. It is responsible for sense of
1. Smell
2. Taste
3. Hearing
4. Vision
Largest cranial nerve in our body is
1. Facial
2. Trigeminal
3. Vagus
4. Olfactory
Which of the following cranial nerve has longest route in periphery?
1. I
2. IV
3. X
4. XI

11. With the stimulation of parasympathetic nervous system the pupil will
1. Dilated
2. Constricted
3. Neither
4. Both
The drowsiness after food intake is due to
1. Increased blood flow to intestine
2. Increased blood pressure
3. Increased activity of liver
4. Increased blood flow to the brain
Appetite is controlled by
1. Cortex of brain
2. Hypothalamus
3. Thalamus
4. Stomach
In human body the number of spinal nerves is
1. 12 pairs
2. 31 pairs
3. 31
4. 33