Chapter 14 Peripheral Nervous System

Front 1

Peripheral Nervous System (PNS)

Back 1

all parts of ns that are not brain and spinal cord

Front 2

Ganglia

Back 2

collections of neuronal cell bodies

Front 3

Nerve

Back 3

hundreds to thousands of PNS axons plus associated connective tissue & blood vessels bundled into functional organ

Front 4

A nerve consists of

Back 4

bundles of myelinated axons

Front 5

Endoneurium

Back 5

surrounds each axon

Front 6

Fascicles

Back 6

bundles of axons

Front 7

Perineureum

Back 7

surrounds the fascicles

Front 8

Epineureum

Back 8

surrounds the whole nerve

Front 9

Sensory receptors

Back 9

respond to enviornmental changes called stimuli

Front 10

Mechanoreceptors

Back 10

touch, pressure, vibration, or stretch

Front 11

Thermoreceptors

Back 11

temperature

Front 12

Chemoreceptors

Back 12

chemicals

Front 13

Nociceptors

Back 13

pain

Front 14

Receptors can be classified by

Back 14

location or location of active stimulus

overall structural complexity

Front 15

Exteroreceptors

Back 15

sensitive to external stimuli (ex. pain, pressure, temp.)

Front 16

Interoreceptors

Back 16

responds to internal stimuli (ex. chemicals, stretch, temp.)

Front 17

Proprioceptors

Back 17

respond to position; found in muscles, tendons, joints, ligaments

Front 18

Meissner’s corpuscles

Back 18

receptors for discriminatory and light touch in hairless areas of the body

Front 19

Pacinian, or lamellated, corpuscles

Back 19

stimulated when deep pressure is first applied

Front 20

Ruffini’s corpuscles

Back 20

responds to deep and continuos pressure

Front 21

Muscle spindles

Back 21

detects when a muscle is being stretched and initiate a reflex that resists the stretch.

Front 22

Golgi tendon organs

Back 22

stimulated when the associated muscle stretches the tendon.

Front 23

Joint kinesthetic receptors

Back 23

monitors the stretch in the articular capsules of synovial joints.

Front 24

Cranial nerves

Back 24

emerges from brain

12 pairs

Front 25

Spinal nerves

Back 25

emerges from spinal cord

31 pairs

Front 26

Cranial Nerve I

Back 26

Olfactory
Sensory
Smell

receptors in olfactory epithelium;

nerves pass through cribriform plate of the ethmoid to the olfactory bulb;

fracture of ethmoid can result in anosmia

Front 27

Cranial Nerve II

Back 27

Optic
Sensory
Vision

receptors in retina of eye;

optic nerves pass through optic foramen, partially cross over at the optic chiasma;

visual defects are called anopsias

Front 28

Cranial Nerve III

Back 28

Oculomotor
Mixed - Sensory, Somatic, Autonomic
Proprioception, Movement of upper eyelid & eyeball, alters lens for near vision

chiefly motor nerves to 4 of the 6 eye muscles,the eyelid, iris, and lens;

nerves pass through the superior orbital fissure of the ethmoid;

Front 29

Ptosis

Back 29

eyelid droops (oculofactory)

Front 30

External strabismus

Back 30

focusing becomes difficult (oculofactory)

Front 31

Cranial nerve IV

Back 31

Trochlear
mixed - sensory & somatic
Proprioception, movement of eyeball

primary motor nerves to the superior oblique muscle of the eye;

damage results in inability to rotate eye inferiolaterally

Front 32

Cranial nerve V

Back 32

Trigeminal
mixed - sensory & somatic
conveys impulses for touch, pain & temp. sensations, chewing

largest cranial nerve with 3 divisions;

opthalmic
maxillary
mandibular

Front 33

Ophthalmic division

Back 33

passes through the superior orbital fissure;

fibers from nasal cavity, cornea, lacrimal gland;

tested by attempting to elicit corneal reflex

Front 34

Maxillary division

Back 34

passes through the foramen rotundum;

fibers from nasal cavity, palate, upper teeth, cheeks, lower eyelid;

tested with pin pricks and hot and cold objects

Front 35

Mandibular division

Back 35

passes through the foramen ovale; to/from tongue lower teeth, chin;

tested by strength of jaw opening and closing, and lateral jaw movement

Front 36

Tic doulereux

Back 36

inflammation of the trigeminal;

results in severe pain from slight stimuli;

partly treatable with drugs; in severe cases, the nerve is severed to relieve pain

Front 37

Cranial Nerve VI

Back 37

Abducens
mixed - Sensory & Somatic
Proprioception & movement of eyeball

primarily motor to lateral rectus muscle of eye

Front 38

Internal strabismus

Back 38

eye can't move laterally (Abducen)

Front 39

Cranial Nerve VII

Back 39

Facial
Mixed - Sensory, Somatic, Autonomic
Taste, facial expression, secretion of tears & saliva

somatic motor nerves run through internal acoustic meatus then stylomastoid foramen of temporal to muscles of facial expression, palate, tongue, salivary glands

parasympathetic motor nerves to lacrimal, nasal, salivary glands;

sensory nerves from anterior part of tongue;

damage results in loss of taste, inability to tear, asymmetry of face;

Front 40

Bell’s palsy

Back 40

paralysis of facial muscles, usually on 1 side, eyelid droop;

it is the result of a Herpes virus infection of the facial nerve