Peripheral Nervous System

• links that connect the outside world to the CNS

• includes all neural structures outside the brain and spinal cord

  • sensory receptors

  • peripheral nerves

  • ganglia

  • efferent motor ending

• dendritic end organs, or parts of other cell types, specialized to respond to a stimulus

• classification

  • stimulus type

  • location in the body

  • structural complexity

What are the classifications of sensory receptors?

• generate impulses when deformed by a mechanical force

  • touch

  • pressure

  • vibration

  • stretch

• sensitive to temperature changes

• respond to light energy

• respond to chemicals in solution and concentrations of chemicals

  • molecules that are smelled or tasted

  • changes in blood or interstitial fluid

• pain receptors

  • respond to potentially damaging stimuli

    • dermis: glass, sunburn, stab, splinter

• respond to a stimuli which arise outside the body

  • most are at or near the body

  • touch, pressure, pain, temperature receptors in the skin

  • most of the receptors are found in the special senses - vision, hearing, taste, smell, equilibrium

• aka viseroceptors

• respond to stimuli which arise within the body

  • located within the visceral organs and blood vessels

  • monitor a variety of stimuli including chemical changes, tissue stretch, and temperature

• provide info regarding the position of the body in space

• monitor how much organs containing these receptors are stretched

  • located in muscles, tendons, and joints (bladder & intestines)

• proprioceptor

• happens at tendon site

• proprioceptors

• helps at the site of muscle

What kind of structural complexity?

• modified dendritic nerve endings of sensory neurons

• located throughout the body

• monitor most types of general sensory information

• widely distributed

What kind of structural complexity?

• sense organs

• localized collections of many types of cells

• eyes, taste buds

Sensory receptors are classified according to stimulus type, body location, and ….

Nociceptors are …. receptors

Receptors that provide information about the position of the body in space are called….

Vision, hearing, taste and smell are all stimuli monitored by the…..

Changes in tension in muscles and tendons are monitored by…

• bundles of neuron fibers (processes) found outside the CNS

• 31 pairs of spinal

• 12 pairs of cranial

• types

  • sensory

  • motor

  • mixed

contains sensory fibers only

contain motor nerves only

contains both motor and sensory fibers

How many cranial nerves are there?

How many spinal nerves are there?

• attached to the spinal cord

• all are mixed

• named for their association with the vertebrae's

• occur in pairs

  • cervical

  • thoracic

  • lumbar

  • sacral

  • coccygeal

8 pairs of spinal nerve

12 pairs of spinal nerves

5 pairs of spinal nerves

5 pairs of spinal nerves

1 pair of spinal nerve

• sites of attachment to the spinal cord

• dorsal

• ventral

contains motor fibers which exit the anterior horn

contains sensory fibers that access the posterior horn

contains the cell bodies of the sensory neurons

• branches

• posterior (dorsal)

• anterior (ventral)

provides sensory and motor intervention to the skin and muscle of the back

innervates the ventrolateral surface (skin), structures in the body wall, and the extremities

specific areas of the skin monitored by each spinal nerve

• interlacing nerve networks, formed by the joining of the anterior ramus (rami) of certain spinal nerves

• located in the cervical, lumbar, sacral regions of the cord

• none between T2 - T12

• named for the area supplied

plexus names

• supply the muscles of the neck & diaphragm

• C1-C5

• supply the shoulder girdle & arm

• C5-T1

• supplies the pelvic girdle & thigh

• L1-L4

• supplies the muscles of the leg

• L4-S4

What are the sympathetic NS plexus?

• top of gut

• nerves radiate in sun beam look

• boxers, wrestlers

ganglion and radiating nerves of the sympathetic system in the pit of stomach

• fibers travel to the periphery via different routes

• each muscle receives innervation from more than one spinal nerve

• damage to one spinal root or segment can not completely paralyze a muscle

• arise from the brain

• primarily serve the head and neck

• some sensory only

• some motor only

• some mixed

• naming

  • function

  • roman numeral

    • according to the position on the brain (anterior to posterior)

What does vagus mean in latin?

• sensory

• smell

• I

• sensory

• vision

• II

• motor

• contraction of eye muscles

• III

• motor

• contraction of one eye muscle (vertical)

• IV

• mixed

• sensory - from face

• motor - chewing muscles

• V

• motor

• contraction of one eye muscle (horizontal)

• VI

• mixed

• motor - facial expressions, salivary & lacrimal glands

• sensory - taste

• VII

• sensory

• balance and hearing

• VIII

• mixed

• motor - swallowing & salvia production

• sensory - taste

• IX

• mixed

• sensory & motor - pharynx, larynx, & viscera

• X

• motor

• activates sternocleidomastoid and trapezius muscle

• XI

• motor

• control of tongue movements

• XII

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