1. Peripheral Nervous System

2. PNS
Refers to all nerves found outside of the CNS Classified as: Mixed Sensory (afferent) Motor (efferent)

3. Cranial Nerves
12 pairs that serve mostly the head and neck Vagus nerves extend to thoracic and abdominal cavities Most are mixed; three are sensory only Olfactory Optic Vestibulocochlear

4. Cranial Nerves
I Olfactory II Optic III Oculomotor-4 motor fibers to eye muscles IV Trochlear-1 motor fiber to eye muscles V Trigeminal –mixed; sensory for face & motor for chewing VI Abducens-motor to eye muscles
VII Facial nerve-sensory for taste; motor to face VIII Vestibulocochlear IX Glossopharyngeal-sensory for taste; motor to pharynx X Vagus-sensory and motor for pharynx, larynx, and viscera XI Accessory – motor to neck and upper back XII Hypoglossal – motor to tongue

5. Spinal Nerves
A pair at each level of vertebrae for a total of 31 Formed by combination of ventral & dorsal roots of spinal cord Ventral rami – form plexuses for the anterior Dorsal rami – serve skin and muscles of posterior trunk of the spinal cord

6. Autonomic Nervous System (Involuntary)
Motor subdivision of PNS
Consists of only motor nerves
Regulate activities of cardiac/smooth muscles & glands
Two subdivisions: Sympathetic
Parasympathetic

7. Sympathetic Anatomy Originates from T1 through L2
Short pre-ganglionic neuron and long post-ganglionic neuron
NT = norepinephrine and epinephrine
Function
Fight-or-flight
Respond to unusual stimuli to increase activities
“E” division
Exercise
Excitement
Emergency
Embarrasment

8. Parasympathetic Anatomy
Originates from the brain stem and S1 through S4
Terminal ganglia at effector organs
NT = acetylcholine
Function “Housekeeping” Maintains daily necessary body functions “D” division Digestion Defacation Diuresis

9. Developmental aspects
Formed during first month of embryonic development
Any maternal infection can have extremely harmful effects
Hypothalamus is one of the last areas to develop
No more neuron formed after birth; growth/maturation continues several years
Brain reaches maximum weight as young adult