Peripheral Nervous System

peripheral nervous system

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

sensory receptors

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

• classification

  • stimulus type

  • location in the body

  • structural complexity

stimulus type, location in the body, and structural complexity

What are the classifications of sensory receptors?

mechanoreceptors

• generate impulses when deformed by a mechanical force

  • touch

  • pressure

  • vibration

  • stretch

thermoreceptors

• sensitive to temperature changes

photoreceptor

• respond to light energy

chemoreceptor

• respond to chemicals in solution and concentrations of chemicals

  • molecules that are smelled or tasted

  • changes in blood or interstitial fluid

nociceptors

• pain receptors

  • respond to potentially damaging stimuli

    • dermis: glass, sunburn, stab, splinter

exteroceptors

• 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

interceptors

• 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

proprioceptors

• 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)

golgi tendon organ

• proprioceptor

• happens at tendon site

muscle spindle

• proprioceptors

• helps at the site of muscle

simple

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

complex

What kind of structural complexity?

• sense organs

• localized collections of many types of cells

• eyes, taste buds

structural complexity

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

pain

Nociceptors are …. receptors

proprioceptors

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

exteroceptors

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

proprioceptors

Changes in tension in muscles and tendons are monitored by…

nerves

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

• 31 pairs of spinal

• 12 pairs of cranial

• types

  • sensory

  • motor

  • mixed

sensory nerve

contains sensory fibers only

motor nerves

contain motor nerves only

mixed nerves

contains both motor and sensory fibers

12

How many cranial nerves are there?

31

How many spinal nerves are there?

Spinal nerves

• attached to the spinal cord

• all are mixed

• named for their association with the vertebrae's

• occur in pairs

  • cervical

  • thoracic

  • lumbar

  • sacral

  • coccygeal

cervical

8 pairs of spinal nerve

thoracic

12 pairs of spinal nerves

lumbar

5 pairs of spinal nerves

sacral

5 pairs of spinal nerves

coccygeal

1 pair of spinal nerve

roots

• sites of attachment to the spinal cord

• dorsal

• ventral

ventral root

contains motor fibers which exit the anterior horn

dorsal root

contains sensory fibers that access the posterior horn

dorsal root ganglia

contains the cell bodies of the sensory neurons

rami

• branches

• posterior (dorsal)

• anterior (ventral)

posterior (dorsal) ramus

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

anterior (ventral) ramus

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

dermatomes

specific areas of the skin monitored by each spinal nerve

plexuses

• 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

cervical, brachial, lumbar, sacral

plexus names

cervical plexus

• supply the muscles of the neck & diaphragm

• C1-C5

brachial plexus

• supply the shoulder girdle & arm

• C5-T1

lumbar plexus

• supplies the pelvic girdle & thigh

• L1-L4

sacral plexus

• supplies the muscles of the leg

• L4-S4

solar and celiac

What are the sympathetic NS plexus?

solar plexus

• top of gut

• nerves radiate in sun beam look

• boxers, wrestlers

celiac plexus

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

plexuses

• 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

cranial nerves

• 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)

wandering

What does vagus mean in latin?

olfactory

• sensory

• smell

• I

optic

• sensory

• vision

• II

oculomotor

• motor

• contraction of eye muscles

• III

trochlear

• motor

• contraction of one eye muscle (vertical)

• IV

trigeminal

• mixed

• sensory - from face

• motor - chewing muscles

• V

abducens

• motor

• contraction of one eye muscle (horizontal)

• VI

facial

• mixed

• motor - facial expressions, salivary & lacrimal glands

• sensory - taste

• VII

auditory (vestibulocoochlear)

• sensory

• balance and hearing

• VIII

glossopharyngeal

• mixed

• motor - swallowing & salvia production

• sensory - taste

• IX

vagus

• mixed

• sensory & motor - pharynx, larynx, & viscera

• X

spinal accessory

• motor

• activates sternocleidomastoid and trapezius muscle

• XI

hypoglossal

• motor

• control of tongue movements

• XII

endoneurium

identify 1

perineurium

identify 2

epineurium

identify 3

axon

identify 4

myelin sheath

identify 5

fascicle

identify 6

blood vessels

identify 7

olfactory (I)

identify 1

oculomotor (III)

identify 2

trigeminal (V)

identify 3

abducens (VI)

identify 4

glossopharyngeal (IX)

identify 5

hypoglossal (XII)

identify 6

optic (II)

identify 7

trochlear (IV)

identify 8

facial (VII)

identify 9

auditory/vestibulocohlear (VIII)

identify 10

vagus (X)

identify 11

accessory (XII)

identify 12