SHS 280 Midterm

OOOT TAFAG VAH

Olfactory

Optic

Oculomotor

Trochlear

Trigeminal

Abducens

Facial

Auditory and Vestibular

Glossopharyngeal

Vagus

A(spinal) Acesseory

Hypoglossal

How are cranial nerves classified (3 classifications)

1. Info types --> general vs special

2. Muscles types --> skeletal vs visceral (internal)

3. Fiber types --> afferent vs efferent

General vs Special (give example)

Special refers to innervation of specialized systems only found in a small part of the body

• ex: general = pain (happens everywhere), special = vision (localized)

Skeletal vs Visceral

Skeletal = motor and sensory functions in muscles attached to bones

Visceral = motor and sensory function vital for organs

Which cranial nerves are afferent fibers, efferent fibers, or both?

Afferent fibers --> I, II, VIII

Efferent fibers --> III, IV, VI, XI, XII

Both --> V, VII, IX, X

How do cranial nerves project?

Unilaterally (ipsi or contra) and bilaterally

Cranial Nerve I

Olfactory

Olfactory is cranial nerve ___

I

Cranial Nerve II

Optic

Optic is cranial nerve ___

II

Cranial Nerve III

Oculomotor

Oculomotor is cranial nerve ___

III

Cranial Nerve IV

Trochlear

Trochlear is cranial nerve ___

IV

Cranial Nerve V

Trigeminal

Trigeminal is cranial nerve ___

V

Cranial Nerve VI

Abducens

Abducens is cranial nerve ___

VI

Cranial Nerve VII

Facial

Facial is cranial nerve ___

VII

Cranial Nerve VIII

Vestibulocochlear

Vestibulocochclear is cranial nerve ___

VIII

Cranial Nerve IX

Glossopharyngeal

Glossopharyngeal is cranial nerve ___

IX

Cranial Nerve X

Vagus

Vagus is cranial nerve ___

X

Cranial Nerve XI

Spinal accessory

Spinal accessory is cranial nerve ___

XI

Cranial Nerve XII

Hypoglossal

Hypoglossal is cranial nerve ___

XII

I: Olfactory

Related to sense of smell

I: How often are olfactory receptors replaced?

Every 30-60 days

I: How can degeneration of olfactory cells occur?

They occur with age or damage

I: What are 3 disorders resulting from olfactory damage? Describe them

Anosmia --> a lack of sense of smell

Hyposmia --> reduction in ability to smell

Hyperosmia --> a hyperactive sense of smell

II: Optic

Carries visual info from the eyes to the brain

II: What is the pathway for carrying info from eyes to brain?

Retina --> lateral geniculate --> visual cortex

II: What is the result of damage dependent on?

Location of the lesion

III: Occulomotor

Controls most of the muscles for moving the eyes, pupil constriction (small), lens adjustment on nearby objects

III: What would happen if the nerve was lesioned?

You lose your ability to focus near or far, and can't move your eyes in certain directions

IV: Trochlear

Associated with the position of the eyes

IV: The nerve sends its signals to where?

Superior oblique muscles

V: Trigeminal

Contains sensory and motor nerves

V: What are the sensory nerves for? What about the motor nerves?

Sensory nerves for face, head, oral cavities

Motor nerves for muscles of chewing/speech sound production

V: What does damage to this nerve result in?

• Ipsilateral loss of sensation (face, tongue, teeth, mouth, gum, cavities)

• Bilateral jaw paralysis

• Trigeminal neuralgia

V: Trigeminal Neuralgia

Incredibly painful sensation, generally triggered by light touches to the face

VI: Abducens

Involved in lateral movement of the eye

VI: What area of the brain controls eye movement across different nerves?

The brainstem gaze

Which 3 nerves are all involved in eye movement?

III, IV, VI

VII: Facial

• Controls muscles involved in facial expression and stapedial reflex

• Mediates taste sensation in anterior 2/3 of tongue

VI: Stapedial Reflex

When there's is a loud sound, it becomes louder because the muscle connected to the stapes vibrates

VII: Vestibulocochlear

Related to hearing and balance

VII: T/F: The auditory and vestibular portions that make up this cranial nerve are often discussed as separate nerves

True

VII: What can its lesions impact?

Hearing, balance, or both

What other nerve is is balance info coming from other than the vestibular nerve?

Cranial nerve II

IX: Glossopharyngeal

Involved with touch, pain, tension, and temperature sensations from the pharynx, tonsils, eustachian tube, middle ear cavity, soft palate

• Also involved with swallowing and talking

IX: Taste sensation for ___ ___ of the tongue

Posterior 1/3

IX: What does damage to this nerve result in?

Swallowing difficulties, loss of gag reflex, loss of taste sensation from ipsilateral posterior 1/3 of tongue

X: Vagus

Regulates cardiac muscles, stomach, esophagus and pharynx (swallowing), larynx (phonation)

XI: Spinal Accessory

Involved in head rotation and shoulder elevation (shrugging)

XI: What does damage to this nerve result in?

An impaired ability to rotate the head laterally and raise the shoulders/shrug

XII: Hypoglossal

Involved in tongue movement and has unilateral innervation

XII: What does damage to this nerve result in?

• Chewing difficulty

• Tongue deviation to side of lesion

• Ipsilateral paralysis of the tongue --> it's wrinkled and atrophy

XII: What can bilateral damage result in?

Profound difficulty swallowing, eating, and speaking

Describe the relationship between one cranial nerve and one function

1 cranial nerve can control multiple functions, and multiple cranial nerves can control 1 function

What are the 3 ways speech sounds are classified?

1. Manner

2. Place

3. Voicing

Manner

Speech sounds are made by partially or completely blocking the air flow

Manner examples

• Liquids (l/r)

• Fricatives (f/v) --> partial closure

• Stops (p/b)

• Nasal (m/n)