The peripheral nervous system has two main subsystems - the somatic nervous system and the autonomic nervous system. The autonomic nervous system can be further divided into the sympathetic and parasympathetic nervous systems. The sympathetic nervous system prepares the body for fight or flight responses while the parasympathetic nervous system helps with rest and digestion. There are also 31 pairs of spinal nerves that carry signals between the brain/spinal cord and the rest of the body. The cranial nerves similarly connect the brain to different parts of the head and neck.

1. PERIPHERAL NERVOUS
SYSTEM

2. INTRODUCTION
• The nervous system is the controlling system of the body and
is composed of nerve cells and organs.
• It is further classified into the central nervous system and the
peripheral nervous system.
• The central nervous system comprises the brain and the spinal
cord.
• The peripheral nervous system comprises the network of nerves
connected to the brain and the spinal cord

4. Peripheral nervous system also has two subsystems:
• Somatic nervous system: This includes muscles that can
control, plus all the nerves throughout your body that carry
information from senses. That sensory information
includes sound , smell, taste and touch.
• Autonomic nervous system: This is the part of nervous
system that connects brain to most of the internal organs.

5. AUTONOMIC NERVOUS SYSTEM (ANS):
• It is the part of nervous system that deals with the involuntary
movements.
• It is also known as visceral nervous systems.
• It works under the conscious and unconscious conditions and
maintain the involuntary functions.
• It control automatically, pumping of blood, beating of heart,
contraction of blood vessel, lungs and GI tract, secretion of
saliva, lacrimal fluid etc

6. FUNCTION OF THE AUTONOMIC
NERVOUS SYSTEM
•
The autonomic nervous system controls internal body processes such as
the following:
• Blood pressure
• Heart and breathing rates
• Body temperature
• Digestion
• Metabolism (thus affecting body weight)
• The balance of water and electrolytes (such as sodium and calcium)
• The production of body fluids (saliva, sweat, and tears)
• Urination
• Defecation
• Sexual response

7. TYPES OF ANS
• Sympathetic nervous system: This system activates body
processes that help you in times of need, especially times of
stress or danger. This system is responsible for your body’s
“fight-or-flight” response.
• Parasympathetic nervous system: This part of your
autonomic nervous system does the opposite of your
sympathetic nervous system. This system is responsible for the
“rest-and-digest” body processes.

8. SYMPATHETIC NERVOUS SYSTEM
• The SNS governs the "fight or flight" response .
• The origin of the sympathetic nervous system is found within the thoracic and lumbar
segments of the spinal cord also known as the Thoracolumbar division (T1 to L2,3),
basically in the middle section of the length of the spinal cord
• Fibers from the SNS innervate tissues in almost every organ system and provide
physiological regulation over diverse body processes including pupil diameter, gut motility
(movement), and urinary output.
• The main overall end effect of the SNS is to prepare the body for physical activity, a whole-
body reaction affecting many organ systems throughout the body to redirect oxygen-rich
blood to areas of the body needed during intense physical demand

9. • The sympathetic pathway can be divided into three following components:
• The preganglionic neurons : travels from its origin in the brain or spinal
cord to a ganglion (collection of cytons outside the CNS)..
• The sympathetic ganglia : are autonomic ganglia of the sympathetic nervous
system
• Ganglia are 20,000 to 30,000 afferent and efferent nerve cell bodies that run
along on either side of the spinal cord.
• Sympathetic ganglia can be divided into two major groups, paravertebral and
prevertebral (or preaortic), on the basis of their location within the body. .
• Paravertebral ganglia generally are located on each side of the vertebrae and
are connected to form the sympathetic chain, or trunk.

10. • The three cervical sympathetic ganglia are
• the superior cervical ganglion
• the middle cervical ganglion
• the cervicothoracic ganglion
• The three preaortic ganglia are
• the celiac
• superior mesenteric,
• inferior mesenteric.
• Lying on the anterior surface of the aorta, preaortic ganglia provide axons that are
distributed with the three major gastrointestinal arteries arising from the aorta.
• The postganglionic neurons : begins in and travels from the ganglion to the smooth
muscle or gland being innervated

12. FUNCTIONS OF SNS
• Eyes: Enlarge your pupils to let more light in and improve your vision.
• Heart: Increase your heart rate to improve the delivery of oxygen to
other parts of your body.
• Lungs: Relax your airway muscles to improve oxygen delivery to your
lungs.
• Digestive tract : Slow down your digestion so its energy is diverted to
other areas of your body.
• Liver : Activate energy stores in your liver to an energy that can be used
quickly.
• These effects help you in situations where you might need to think or act
quickly.

13. PARASYMPATHETIC NERVOUS SYSTEM
• The parasympathetic nervous system predominates in quiet “rest and digest”
conditions .
• The parasympathetic nervous system, or craniosacral division, has its origin
in neurons with cell bodies located in the brainstem nuclei of four cranial
nerves—the oculomotor (cranial nerve III), the facial (cranial nerve VII), the
glossopharyngeal (cranial nerve IX), and the vagus (cranial nerve X)—and in
the second, third, and fourth segments of the sacral spinal cord.
• The main purpose of the PNS is to conserve energy to be used later and to
regulate bodily functions like digestion and urination.

15. FUNCTIONS OF PSNS
• Salivation: As part of its rest-and-digest function, the PSNS stimulates production of saliva,
which contains enzymes to help in food digest.
• Lacrimation: ie making tears. Tears keep eyes lubricated, preserving their delicate tissues.
• Urination: The PSNS contracts the bladder, which squeezes it so urine can come out.
• Digestion: The PSNS stimulates the release of saliva to promote digestion. It also enacts
peristalsis, or the movement of the stomach and intestines, to digest food as well as release
bile for the body to digest fats.
• Defecation: The PSNS constricts the sphincters in the intestine and moves digested food
material down the digestive tract so a person can have a bowel movement.

17. CRANIAL NERVES.
•The cranial nerves are a set of 12 paired nerves in the
back of your brain.
•Cranial nerves send electrical signals between your
brain, face, neck and torso.
• Cranial nerves help in taste, smell, hear and feel
sensations.
•They also help to make facial expressions, blink your
eyes and move your tongue.

18. ORIGIN OF THE CRANIAL NERVES
• The olfactory nerve (CN I) and optic nerve (CN II) originate from the cerebrum. Cranial
nerves III – XII arise from the brainstem
• They can arise from a specific part of the brainstem (midbrain, pons or medulla), or from
a junction between two parts:
• Midbrain– the trochlear nerve (IV) comes from the posterior side of the midbrain. It has
the longest intracranial length of all the cranial nerves.
• Midbrain-pontine junction – oculomotor (III).
• Pons – trigeminal (V).
• Pontine-medulla junction – abducens, facial, vestibulocochlear (VI-VIII).
• Medulla oblongata
• Posterior : glossopharyngeal, vagus, accessory (IX-XI).
• Anterior : hypoglossal (XII).

19. • The cranial nerves are numbered by their location on the brainstem (superior to
inferior, then medial to lateral) and the order of their exit from the cranium (anterior
to posterior)

21. TYPES OF CRANIAL NERVES WITH FUNCTIONS
• Olfactory nerve: Sense of smell.
• Optic nerve: Ability to see.
• Oculomotor nerve: Ability to move and blink your eyes.
• Trochlear nerve: Ability to move your eyes up and down or back and forth.
• Trigeminal nerve: Sensations in your face and cheeks, taste and jaw movements.
• Abducens nerve: Ability to move your eyes.
• Facial nerve: Facial expressions and sense of taste.
• Auditory/vestibular nerve: Sense of hearing and balance.
• Glossopharyngeal nerve: Ability to taste and swallow.
• Vagus nerve: Digestion and heart rate.
• Accessory nerve (or spinal accessory nerve): Shoulder and neck muscle movement.
• Hypoglossal nerve: Ability to move your tongue.

22. 1.The olfactory nerves are associated with the function of smell.
the type of modality is sensory.
2. The optic nerves are associated with the function of vision.
The type of modality of the optic nerve is sensory,
3. The oculomotor nerve is also associated with vision , This nerve also
functions in pupillary response to help control the size of the pupils as it
responds to light, dilating and constricting the pupils
The modality of this cranial nerve is motor.
4. The trochlear nerve controls the muscles that are responsible for downward,
outward, and inward eye movements.
The trochlear nerve is motor.
5. The trigeminal nerve is the largest of the cranial nerves and can be further
divided into three divisions: ophthalmic, maxillary, and mandibular.

23. • The ophthalmic division sends information from the scalp, forehead, and upper eyelids (the
upper parts of the head) and is sensory in modality.
• The maxillary division sends information from the middle of the head, such as cheeks,
lower eyelids, upper lip, and nasal cavity. This is also sensory .
• The mandibular division sends both sensory and motor information .
6. The abducens nerve is another nerve that controls a muscle of the eye, responsible for
outward eye movements such as looking to the side.
This nerve sends motor information
7. Facial nerves have both sensory and motor functions, such as collecting information from
the taste buds of the tongue, controlling muscle movements required for facial expressions, and
supplying glands that produce saliva and secrete tears.
8. The vestibulocochlear nerve is associated with the function of hearing and consists of two
divisions: cochlear and vestibular.
This information is sensory

24. 9. The glossopharyngeal nerve has both motor and sensory functions
• This nerve sends sensory information from the external ear and middle ear cavity , the back
part of the tongue , and from the sinuses at the back of the throat .
• This nerve also sends motor information from two salivary glands called parotid glands ,
and movement from a muscle at the back of the throat called the stylopharyngeus .
10. The vagus nerve has a variety of functions and is the longest and most branched of all the
cranial nerves with sensory, motor, and autonomic fibers.
It receives sensory information from the ear canal as well as the larynx and pharynx, which
are parts of the throat , information from the organs of the chest and trunk such as the heart
and intestines , and a sense of taste from the root of the tongue and information from the
smooth muscles of parts of the throat .
11.The spinal accessory nerve has motor functions associated with the muscles and
movements of the head, neck, and shoulders.
12. The hypoglossal nerve is responsible for most of the movements in the tongue.

25. EXITING THE SKULL AND EXTRACRANIAL
COURSE
• After emerging from the brain, the cranial nerves travel within the skull, and some
must leave it in order to reach their destinations.
• Often the nerves pass through holes in the skull, called foramina, as they travel to
their destinations.
• Other nerves pass through bony canals, longer pathways enclosed by bone.
• These foramina and canals may contain more than one cranial nerve and may also
contain blood vessels.

26. Location Nerve
cribriform plate Terminal nerve (0)
cribriform plate Olfactory nerve (I)
optic foramen Optic nerve (II)
superior orbital fissure
Oculomotor (III)
Trochlear (IV)
Abducens (VI)
Trigeminal V1
(ophthalmic)
foramen rotundum
Trigeminal V2
(maxillary)
foramen ovale
Trigeminal V3
(mandibular)
stylomastoid foramen Facial nerve (VII)
internal auditory canal Vestibulocochlear (VIII)
jugular foramen
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
hypoglossal canal Hypoglossal (XII)

27. SYMPTOMS OF CRANIAL NERVE DISORDERS
• Loss of sensation in a part of the face
• Weakness
• Numbness of the face
• Pain
• Tingling sensation
• Changes in vision
• Weak or paralyzed muscles

28. SPINAL NERVES
• A spinal nerve is a mixed nerve, which carries motor, sensory, and
autonomic signals between the spinal cord and the body.
• In the human body there are 31 pairs of spinal nerves, one on each side
of the vertebral column.
• These are grouped into the
corresponding cervical, thoracic, lumbar, sacral and coccygeal regions
of the spine.
• There are eight pairs of cervical nerves, twelve pairs of thoracic
nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and
one pair of coccygeal nerves.
• The spinal nerves are part of the peripheral nervous system.

29. • Each spinal nerve is a mixed nerve, formed from the combination of nerve
root fibers from its dorsal and ventral roots.
• The Dorsal root : the afferent sensory root and carries sensory information to
the brain.
• The Ventral root : the efferent motor root and carries motor information from
the brain.
• The spinal nerve emerges from the spinal column through an opening
(intervertebral foramen) between adjacent vertebrae.
• Outside the vertebral column, the nerve divides into branches.
• Dorsal Ramus
• Ventral Ramus

30. • The dorsal ramus contains nerves that serve the posterior
portions of the trunk carrying visceral motor, somatic motor,
and somatic sensory information to and from the skin and
muscles of the back .
• The ventral ramus contains nerves that serve the remaining
anterior parts of the trunk and the upper and lower limbs
carrying visceral motor, somatic motor, and sensory
information to and from the ventrolateral body surface,
structures in the body wall, and the limbs

31. TYPES OF SPINAL NERVE
• Cervical nerves:
• The cervical nerves are the spinal nerves from the cervical vertebrae in
the cervical segment of the spinal cord. Although there are seven cervical
vertebrae (C1–C7), there are eight cervical nerves C1–C8.
• C1–C7 emerge above their corresponding vertebrae, while C8 emerges
below the C7 vertebra.
• The posterior distribution includes the suboccipital nerve (C1), the greater
occipital nerve (C2) and the third occipital nerve (C3). The anterior
distribution includes the cervical plexus (C1–C4) and brachial plexus (C5–
T1).

32. • Thoracic nerves
• The thoracic nerves are the twelve spinal nerves emerging from the thoracic
vertebrae.
• Each thoracic nerve T1–T12 originates from below each
corresponding thoracic vertebra.
• Branches also exit the spine and go directly to the paravertebral ganglia of
the autonomic nervous system where they are involved in the functions of
organs and glands in the head, neck, thorax and abdomen.
• Lumbar nerves
• The lumbar nerves are the five spinal nerves emerging from the lumbar
vertebrae.
• They are divided into posterior and anterior divisions

33. • Posterior divisions
• The medial branches of the posterior divisions of the lumbar nerves run close to the
articular processes of the vertebrae and end in the multifidus muscle.
• Anterior divisions
• The anterior divisions of the lumbar nerves (rami anteriores) increase in size from above
downward.
• They are joined, near their origins, by gray rami communicantes from the lumbar
ganglia of the sympathetic trunk.

34. • Sacral nerves
• The sacral nerves are the five pairs of spinal nerves which exit the sacrum at
the lower end of the vertebral column.
• The roots of these nerves begin inside the vertebral column at the level of
the L1 vertebra, where the cauda equina begins, and then descend into the
sacrum
• There are five paired sacral nerves, half of them arising through the sacrum
on the left side and the other half on the right side.
• Each nerve emerges in two divisions: one division through the anterior sacral
foramina and the other division through the posterior sacral foramin.

35. • Coccygeal nerve
• The bilateral coccygeal nerves, Co, are the 31st pair of spinal nerves. It
arises from the conus medullaris, and its ventral ramus helps form
the coccygeal plexus.
• It does not divide into a medial and lateral branch.
• Its fibers are distributed to the skin superficial and posterior to
the coccyx bone via the anococcygeal nerve of the coccygeal nerve
plexus.

37. QUESTION BANK
2 MARKS
1. Define : Nervous system , cranial nerves, spinal nerves
2. Which cranial nerve is responsible for facial expression and sense of taste?
3. Write name of cranial no. 6 and 9
4. Which cranial nerve is responsible for eye & tongue movement.
5. Write function of oculomotor & olfactory nerve?
6. Write function of cervical spinal nerve?
7. Write function of lumbar spinal nerve?
8. Enlist 4 symptoms of cranial nerve damage.
9. Write function and modality of accessory and auditory cranial nerve.
10. Write origin of trochlear and trigeminal cranial nerve

38. QUESTION BANK
• 5 MARKS.
• Write difference between parasympathetic and sympathetic system (10 points)
• Write a note on cranial nerves.
• Discuss spinal nerve with their specific functions.
• Classify Nervous system and explain Autonomic & peripheral nervous system
• 10 MARKS.
• Classify Nervous system. Compare and contrast Sympathetic and
parasympathetic nervous system.
• Discuss in brief Spinal Nerve.
• Describe types, origin, functions and modality of cranial nerves.