Lecture 19 (4/14)

Question 1

PNS (Overview)

Answer 1

Lies outside of the skull and vertebral columns

The means by which nervous impulses are conveyed to and from the CNS

Made up of two functional systems:
Autonomic Nervous System
Somatic Nervous System

Question 2

Somatic Nervous System

Answer 2

One of two functional systems of the PNS

Has two main components:
Spinal Nerves
Cranial Nerves

Question 3

Cranial Nerves

Answer 3

There are 12 CNs

Most synapse with the CNS in the brainstem

Each of the CNs serves motor info, sensory info, or both

I - Olfactory
II - Optic
III - Oculomotor
IV - Trochlear 
V - Trigeminal 
VI - Abducens
VII - Facial
VIII - Vestibular
IX - Glossopharyngeal
X - Vagus
XI - Spinal Accessory
XII - Hypoglossal

Question 4

Cranial Nerve I

Answer 4

Olfactory

Serves only sensory function

How to test:
The sensation of smell can be tested by having the patient not look at the stimuli or having it wrapped in something and then presenting by asking them to name the smell (onions, peppermint)

Question 5

Cranial Nerve II

Answer 5

Optic

Serves only sensory function

How to test:
Hold a different object in each hand and have arms spread wide. With the patient looking at the center you move your arms inward until they can see the objects

Determine the integrity of the pupil
Shining a light into the eye - if the pupil is ok it will constrict immediately

Question 6

Cranial Nerve III

Answer 6

Oculomotor

Serves only motor function - eye movement

Injury to CN III results:

• in drooping of the eyelid, known as ptosis
• -caused by paralysis to the muscles that raise the eyelid

Patients often complain of double vision (diplopia)

Question 7

Ptosis

Answer 7

Drooping of the eyelid

Question 8

Diplopia

Answer 8

Double vision

Question 9

Cranial Nerve IV

Answer 9

Trochlear

Serves only motor function - eye movement

Injury causes upward deflection of the effected eye during forward gaze - patient may also experience diplopia

Question 10

Cranial Nerve V

Answer 10

Trigeminal

Serves both sensory and motor

Sensory branch has 3 division
Opthalamic
Maxillary
Mandibular

Motor branch

Innervates muscles of mastication
Can be tested by asking the patient to open and close the jaw against resistance

If V is injured patient may not be able to chew

Question 11

Opthalamic Division

Answer 11

Division of the sensory branch of the Trigeminal nerve

Provides sensation to the eye, upper eyelid, the bridge of the nose, and the anterior scalp

Question 12

Maxillary Division

Answer 12

Division of the sensory branch of the Trigeminal nerve

Provides sensation to the cheeks, the nose, upper teeth and lip, the hard palate, and the nasopharynx

Question 13

Mandibular Division

Answer 13

Divison of the sensory branch of the Trigeminal nerve

Provides sensation to the skin of the lower jaw, outer ear, lower teeth and gums, the floor of the mouth, the inside surfaces of the cheek

Question 14

Corneal Reflex

Answer 14

A test in which a cotton swab is dragged against the eyeball to check for the blinking reflex

Question 15

Cranial Nerve VI

Answer 15

Abducens

Serves only motor function - eye movement

Injury causes inward deflection of the effected eye

• patient experiences diplopia when looking toward the side of the effected eye
• patient may also experience nystagmus

Question 16

Nystagmus

Answer 16

Rhythmic oscillation of the eye

Question 17

Cranial Nerve VII

Answer 17

Facial

Serves both sensory and motor

Motor:
Involved in the motor movement of the muscles of the face for facial expression

If damaged the muscles of facial expression may be paralyzed

• Cant close the eyelid tightly, wrinkle the forehead, or pucker the lips
• in some cases the facial muscles of one side can be paralyzed

Sensory:
Involved in taste, specifically involved in the anterior ⅔ of the tongue

Question 18

Cranial Nerve VIII

Answer 18

Vestibular

Serves only sensory function - involved in hearing

To test:
Cause use different tasks, such as whispering into the ear of the patient or using a tuning fork or a ticking clock

Question 19

Cranial Nerve IX

Answer 19

Glossopharyngeal

Serves both sensory and motor

Motor:
Swallowing

Sensory:
Taste: posterior ⅓ of tongue, visceral sensation from palate and oral pharynx

IX and X can be tested together by testing the sensitivity of the posterior wall of the pharynx with a tongue depressor

Question 20

Cranial Nerve X

Answer 20

Vagus

Serves both sensory and motor

Phonation and swallowing - gag reflex

Question 21

Cranial Nerve XI

Answer 21

Spinal Accessory

Serves only motor function - Head movement and shoulder elevation

Injury causes:
Damaged side of the body to droop

Can test by asking the patient to raise his shoulders against resistance

Question 22

Cranial Nerve XII

Answer 22

Hypoglossal

Serves only motor function - tongue movement

Injury to XII can cause the patient’s tongue to deviate toward the side of injury (ipsilateral)

Can test by evaluating the patient’s ability to protrude the tongue and seeing if they can move it from one side or the other. This can also be done against resistance