1. Peripheral Nervous System

2. Peripheral Nervous System (PNS)
Nerves and ganglia outside the central nervous system
Nerve = bundle of neuron fibers
Neuron fibers are bundled by connective tissue

3. PNS: Structure of a Nerve
Endoneurium surrounds each fiber/axon
Groups of fibers are bound into fascicles by perineurium
Fascicles are bound together by epineurium

4. PNS: Classification of Nerves
Mixed nerves
Both sensory and motor fibers
Sensory (afferent) nerves
Carry impulses toward the CNS
Motor (efferent) nerves
Carry impulses away from the CNS

5. Cranial Nerves 12 pairs of cranial nerves
Control head, neck, part of trunk, and upper limbs
Numbered in order and name tells about its function

6. Cranial Nerves
I. Olfactory– sensory, carries impulses for sense of smell
II. Optic—sensory, carries impulses for vision
III. Oculomotor—motor, controls 4 of 6 eye movement muscles, eyelid, lens shape, and pupil size
IV. Trochlear—motor, controls external eye muscles
V. Trigeminal—sensory: conducts impulses from skin of face and mucosa of nose and mouth. Motor: fibers that activate chewing muscles
VI. Abducens—motor, controls muscles that roll the eye laterally

7. Cranial Nerves
VII. Facial—activates muscles of facial expression, lacrimal and salivary glands. Also carries sensory info from the taste buds of anterior tongue.
VIII. Vestibulocochlear—sensory, vestibular branch transmits info for sense of balance, cochlear branch transmits info for sense of hearing
IX. Glossopharyngeal—motor: supplies fibers to the throat that promote swallowing and saliva production. Sensory: transmits info from taste buds of posterior tongue and pressure receptors of the carotid artery
X. Vagus—carries sensory and motor info to the throat, voicebox and abdominal/thoracic viscera

8. Cranial Nerves
XI. Accessory—motor, fibers activate trapezius and sternocleidomastoid muscles
XII. Hypoglossal—motor, control of tongue movements. Sensory—carry impulses from the tongue
Mnemonic Device:
On, On, On, They Traveled And Found Voldemort Guarding Very Ancient Horcruxes

9. PNS: Spinal Nerves
There is a pair of spinal nerves at the level of each vertebrae for a total of 31 pairs
Formed by the combination of the ventral and dorsal roots of the spinal cord
Named for the region from which they arise

10. Spinal Nerves

11. PNS: Anatomy of Spinal Nerves
Spinal nerves divide soon after leaving the spinal cord
Dorsal rami—serve the skin and muscles of the posterior trunk
Ventral rami—form a complex of networks (plexus) for the anterior
The rami, like spinal nerves, contain both motor and sensory fibers

12. Nerve Plexuses
The ventral rami also form complex networks of nerves called plexuses
Plexuses serve the motor and sensory needs of the limbs.

13. PNS: Spinal Nerve Plexuses

14. PNS: Spinal Nerve Plexuses

15. PNS: Distribution of Major Peripheral Nerves of the Upper and Lower Limbs

16. PNS: Distribution of Major Peripheral Nerves of the Lower Limbs