Peripheral Nervous System

(PNS)

AFFERENT

Sensory nerves

(to CNS)

EFFERENT

Motor nerves

(from brain back to body)

SOMATIC FIBERS

Fibers that innervate the body wall

 AUTONOMIC NERVOUS SYSTEM

 Peripheral nerves involved in regulating cardiovascular, respiratory, endocrine

 NERVE

 A bundle of axons, dendrites or both

 MIXED NERVE

 Nerves that contain sensory AND motor axons

 ENDONEURIUM

 delicate connective tissue covering that surrounds and holds each nerve fiber

 FASCICULUS

 A group of nerve fibers

 PERINEURIUM

 sheath of connective tissue that surrounds fasciculus

 EPINEURIUM

 Connective tissue covering that surrounds the entire nerve

OLFACTORY

(CRANIAL NERVE)

Sensory

Function: smell

OPTIC

(CRANIAL NERVE)

Sensory

Function: Vision

OCULOMOTOR

(CRANIAL NERVE)

Motor

Function: 4/6 eye muscles

TROCHLEAR

(CRANIAL NERVE)

Motor

Function: 1/6 eye muscle

TRIGEMINAL

(CRANIAL NERVE)

Both

Function:

(s) Face

(m) chewing

ABDUCENS

(CRANIAL NERVE)

Motor

Function: 1/6 eye muscles

FACIAL

(CRANIAL NERVE)

Both

Function:

(s) Taste

(m) Face

VESTIBULOCOCHLEAR

(CRANIAL NERVE)

Sensory

Function: Balance/hearing

GLOSSOPHARANGEAL

(CRANIAL NERVE)

Both

Function:

(s) Taste

(m) Pharynx

VAGAS

(CRANIAL NERVE)

Both

Function:

(s) Pharynx

(m) Larynx

ACCESSORY

(CRANIAL NERVE)

Motor

Function: Neck/Back

(SCM)

HYPOGLOSSAL

(CRANIAL NERVE)

Motor

Function: Tongue

 SPINAL NERVES

 31 pairs

 DORSAL ROOT GANGLION

 Dorsal root of each spinal nerve recognized by swelling

 PLEXUS

 Spinal nerves in small groups (cervical, brachial, lumbar, sacral)

CERVICAL

(PLEXUS)

8 pairs

BRACHIAL

(PLEXUS)

C5-T1

Supply skin & muscle of upper limbs

LUMBAR

(PLEXUS)

5 pairs

 SACRAL

 5 pairs

 DERMATOME

 Section of skin supplied by single spinal nerve

 MYOTOME

 A skeletal muscle or group of muscles that receive motor axons from single spinal nerve

 REFLEX

 involuntary action

 SOMATOSOMATIC

 Reflex: stimulus of sensory receptors - body to body

 SOMATOVISCERAL

 Reflex: Body to visceral

VISCEROSOMATIC

Reflex: Visceral to body

SOMATIC NERVOUS SYSTEM

Division of PNS, primarily affects skin, muscles, joints and bones

 EXTERORECEPTORS

 Receptors on the outside of our bodies

 CONDITIONED REFLEX

 Being aware of stimuli and purposefully adapt our response

 MECHANICAL RECEPTORS

 Receptors that have to do with the mechanics of the body

MECHANORECEPTORS

M-Receptor: Detect changes in pressure, movement, temperature, or other mechanical forces

PACINIAN CORPUSCLE

M-Receptor: Senses brief touch, pressure, & high-frequency vibrations.

 MEISSNER'S CORPUSCLE

 M-Receptor: Can identify exact location of touch

RUFFINI'S END ORGANS

M-Receptor: Recognize heavy and continuous touch, pressure, steady position and direction of movement

MERKEL'S DISKS

M-Receptor: Function in discriminative touch

 FREE NERVE ENDINGS

 M-Receptors: Detect temperature (i.e., thermal receptors)

 THERMAL RECEPTORS

 Mechanical receptors that detect temperature

 NOCICEPTORS

 M-Receptor: Specific free nerve endings that detect painful stimuli

 PROPRIOCEPTORS

 M-receptor that provide us with information about position and movement

 MUSCLE SPINDLES

 M-Receptor: Stretch receptors that monitor and respond to sudden and excessive lengthening

GAMMA MOTOR NEURON

Innervate muscle spindles

FLACCID

Muscle that offers little resistance to stretch

 HYPOTONIC

 When gamma motor neuron discharge is low

 HYPERTONIC / SPASTIC

 Muscle that offers great resistance to stretch

 GOLGI TENDON ORGANS

 M-Receptor: Respond to increases in tension

 STRETCH REFLEX

 Protective contraction that results when muscle is stretched suddenly or intensely

 DUAL INNERVATION

 Most organs contain neurons from sympathetic and parasympathetic divisions

 TOUCH

 1/5 senses

HEARING

(5 SENSES)

1/5 senses

Vibrations in the air taken in by external ear

opening in externalo ear

 MIDDLE EAR

 Eardrum

Sounds reach tympanic membrane

 OSSICLES

 3 tiny bones in inner ear - Malleus, Incus, Stapes

HAMMER

(MALLEUS)

 1/3 Ossicles

Moves w/eardrum, transfers vibrations to incus

ANVIL

 1/3 Ossicles

Passes vibration to Stapes

STAPES

(STIRRUP)

1/3 Ossicles

Sets fluids in motion, exciting hair receptors

VISION

(5 SENSES)

White of the eye.

6 pairs of extrinsic eye muscles

Window of the eye.

Avascular, transparent. Only human tissue that can be transplanted w/o fear of rejection

1/2 photoreceptors in retina

TASTE

(5 SENSES)

SMELL

(OLFACTION)

(5 SENSES)