1. PERIPHERAL
NERVOUS SYSTEM
(PNS)
Queenie G. Bombase

2. What is Peripheral Nervous System?
 The peripheral nervous system (PNS) is
the division of the nervous
system containing all the nerves that lie
outside of the central nervous system
(CNS).
 Primary role:
 to connect the CNS to the organs, limbs
and skin. These nerves extend from the
central nervous system to the outermost
areas of the body.

4. Somatic Nervous System
 the part of the peripheral nervous system responsible for
carrying sensory and motor information to and from
the central nervous system.
 derives its name from the Greek word soma, which means
"body.“
 responsible for transmitting sensory information as well as for
voluntary movement.
 contains two major types of neurons:
 sensory neurons (or afferent neurons) - carry information
from the nerves to the central nervous system
 motor neurons (or efferent neurons) that carry information
from the brain and spinal cord to muscle fibers throughout
the body.

5. Sensory-Somatic Nervous System
 The sensory-somatic system consists of
› 12 pairs of cranial nerves and
› 31 pairs of spinal nerves.

6.  Cranial Nerves - nerves that emerge directly
from the brain, in contrast to spinal
nerves, which emerge from segments of
the spinal cord. In humans, there are
traditionally twelve pairs of cranial nerves. Only
the first and the second pair emerge from
the cerebrum; the remaining ten pairs emerge
from the brainstem.
 Spinal Nerves - spinal nerves or nerve
roots, branch off the spinal cord and pass out
through a hole in each of the vertebrae called
the Foramen. These nerves carry information
from the spinal cord to the rest of the body, and
from the body back up to the brain.

8. Nerves Type Function
I
sensory olfaction (smell)
Olfactory
vision
II
sensory (Contain 38% of all the axons
Optic
connecting to the brain.)
III
motor* eyelid and eyeball muscles
Oculomotor
IV
motor* eyeball muscles
Trochlear
Sensory: facial and mouth
V
mixed sensation
Trigeminal
Motor: chewing
VI
motor* eyeball movement
Abducens
Sensory: taste
VII
mixed Motor: facial muscles and
Facial
salivary glands
VIII
sensory hearing and balance
Auditory
IX Sensory: taste
mixed
Glossopharyngeal Motor: swallowing
main nerve of the
X
mixed parasympathetic nervous
Vagus
system (PNS)
XI swallowing; moving head and
motor
Accessory shoulder
XII
motor* tongue muscles
Hypoglossal

9.  sensory neurons running from
stimulus receptors that inform the CNS of the stimuli
 motor neurons running from the CNS to
the muscles and glands - called effectors - that
take action.
 It is responsible for monitoring conditions in the
internal environment and bringing about
appropriate changes in them. The contraction of
both smooth muscle and cardiac muscle is
controlled by motor neurons of the autonomic
system.

10. Autonomic Nervous System
 is the part of the peripheral nervous system
responsible for regulating involuntary body
functions, such as blood
flow, heartbeat, digestion and breathing.
 further divided into two branches:
 sympathetic system regulates the flight-or-
fight responses
 parasympathetic system helps maintain
normal body functions and conserves physical
resources.

12.  The autonomic nervous system has two:
 sympathetic nervous system
 parasympathetic nervous system

13. Sympathetic Nervous System
 The sympathetic nervous system is located to
the sympathetic chain, which connects to
skin, blood vessels and organs in the body
cavity. The sympathetic chain is located on
both sides of the spine and consists of
ganglias.

14.  stimulates heartbeat
 raises blood pressure
 dilates the pupils
 dilates the trachea and bronchi
 stimulates glycogenolysis — the conversion of
liver glycogen into glucose
 shunts blood away from the skin and viscera to
the skeletal muscles, brain, and heart
 inhibits peristalsis in the gastrointestinal (GI)
tract
 inhibits contraction of the bladder and rectum
 and, at least in rats and mice, increases the
number of AMPA receptors in the hippocampus
and thus increases long-term potentiation

15. Parasympathetic Nervous System
 he Parasympathetic system is the branch of
the Autonomic Nervous System (ANS)
responsible for the body’s ability to recuperate
and return to a balanced state (known as
"homeostasis") after experiencing pain
or stress.

16.  Parasympathetic stimulation causes:
 slowing down of the heartbeat (as Loewi
demonstrated)
 lowering of blood pressure
 constriction of the pupils
 increased blood flow to the skin and viscera
 peristalsis of the GI tract