1. Peripheral Nervous System
THE NERVOUS SYSTEM
Peripheral Nervous System

2. PNS
Composed of nerves and ganglia outside the CNS

3. Nerve Structure Neuron fibers - axons surrounded by endoneurium
Fasicle – group of neuron fibers surrounded by perineurium
Nerve – several fasicles and blood vessels surrounded by epineurium

4. Nerve Classification Based on direction of impulse
1. Afferent or Sensory – toward CNS
2.Efferent or Motor – away from CNS toward effector (muscle or gland)
3. Mixed Nerves – both sensory and motor *ALL spinal nerves are mixed

5. Cranial Nerves 12 pair – 2 forebrain and 10 brainstem
Go mostly to head and neck – exception is vagus nerve  to abdominal viscera

6. Cranial Nerves I – olfactory = sensory II – optic = sensory
III – oculomotor = motor
IV – trochlear = motor
V – trigeminal = mixed
VI – abducens = motor
VII – facial = mixed
VIII – vestibuchochlear = sensory
IX – glossopharyngeal = mixed
X – vagus = mixed
XI – accessory = motor
XII – hypoglossal = motor

7. Spinal Nerves 31 pairs  ALL ARE MIXED
Formed by combining of dorsal and ventral roots
Approximately ½” long  then splits into rami
Named for region of spinal cord from which they arise
Cervical
Thoracic
Lumbar
Sacral
Coccyx

9. PNS Organization

10. PNS - Autonomic Sympathetic Parasympathetic Fight or Flight
NT= norepinephrine
Resting and Digesting
NT= acetylcholine