Peripheral Nervous System

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Peripheral Nervous System

• Contains
• Sensory receptors
• Peripheral nerves and their ganglia.
• Efferent motor nerve endings.

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Sensory Receptors

• Stimulus Type Classification
• Mechanoreceptors
• Thermoreceptors
• Photoreceptors
• Chemoreceptors
• Nociceptors
• Overstimulation

• Location Classification
• Exteroreceptors
• Interoreceptors
• Proprioreceptors

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Nerve Structure

• Afferent (Sensory) nerves
• Efferent (Motor) Nerves
• Mixed nerves
• Ganglia
• Regeneration of neurons.
• PNS vs. CNS

• Neuromuscular junctions
• Acetylcholine (Ach)
• Acetylcholinesterase

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Cranial Nerves

• Optic Nerve
• Oculomotor Nerve-extrinsic muscles.
• Trochlear NerveExtrinsic muscle.
• Trigeminal NerveFace and chewing muscles.
• AbducensAbducts the eye.
• Facialfacial expression muscles.

• Vestibulocochlearhearing and balance
• Glossopharyngealtongue and pharynx.
• Vagusthorax and abdomen.
• Accessorypart of vagus nerve
• Hypoglossaltongue moving muscles.

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Cranial Nerves
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Spinal Nerves

• 31 pairs
• Supply all parts of the body except the head and
  parts of the neck.
• Cervical spinal nerves8 pairs.
• Thoracic12 pairs
• Lumbar5 pairs
• Sacral5 pairs
• Coccygeal1 pair

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Spinal Nerves
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Reflexes

• Does not involve the brain.
• Spinal Reflexes
• Reflex Arc
• Receptor
• Sensory neuron
• Integration center (interneurons)
• Motor neuron
• effector

• Somatic Reflexes
• Autonomic Reflexes
• Stretch reflexes
• Stretch receptors-muscle spindles.
• Patellar or knee jerk reflex
• Monosynaptic and ipsilateral

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Reflexes

• Withdrawal or Flexor Reflexresponse to pain.
• Polysynaptic, ipsilateral reflexes.
• Plantar reflexdownward flexion of the toes.
• Babinskis signbig toedorsiflexion other toes
  fan laterally.