Cranial nerves

Question 0

motor nerves

Answer 0

their cell bodies are in nuclei within the brain

Question 1

sensory nerves

Answer 1

most of their cell bodies are outside of the brain in ganglia

Question 2

CN 1

Answer 2

Olfactory nerve, sensory (smell)
Olfactory receptors (Superior part of nasal cavity, inferior surface of the cribriform plate along the superior nasal concha) ->olfactory epithelium -> olfactory nerve -> olfactory foramina in the cribriform plate -> olfactory bulbs -> olfactory tracts -> primary olfactory area 28 + limbic system + hypothalamus + habenular nuclei (Ephithalamus) emotional response to odors -> Frontal lobe #11

Question 3

Loss of sense of smell from infections of nasal mucosa, head injuries, meningitis, smoking, cocaine use

Answer 3

Anosmia

Question 4

Reduced ability to smell

Answer 4

hyposmia

Question 5

increased sense of smell

Answer 5

hyperosmia (only sensation reach the cerebral cortex without first synapsing in the thalamus)

Question 6

CN II

Answer 6

Optic Nerve (sensory nerve - optic)
Rods and cones in retina (photoreceptor->Bipolar cell -> Ganglion)
-> Optic nerves -> optic foramen (under pituitary gland) ->optic chiasm (medial half cross opposite site, lateral half does not cross) -> optic tract ->lateral geniculate nucleus in thalamus -> primary visual area #17 Occipital lobe (a few axons go to superior colliculi (tectum) in midbrain

Question 7

cone

Answer 7

Stimulated in bright light, color vision, high acuity, concentrated in the center of retina

Question 8

rod

Answer 8

allow us to see in dim light
no color
low acuity
concentrated in the periphery

Question 9

Bipolar cells

Answer 9

lateral connections

Question 10

Ganglion cell layer

Answer 10

their axons extend posteriorly to optic disc and exit the eye as the optic nerve

Question 11

Optic disc

Answer 11

blind spot

Question 12

blindness due to a defect or loss of 1 or 2 eyes

Answer 12

Anopia
from fractures in orbit, brain lesions, damage along the pathway disease of the nervous system, pituitary gland tumours, cerebral aneurysm

Question 13

Make your eyes trick

Answer 13

CN III (Oculomotor), IV (Trochlear nerve), VI (Abducens nerve)

Question 14

CN III

Answer 14

Oculomotor nerve (Motor, eye movement and upper eye lid)
Nucleus in midbrain -> superior orbital fissure -> superior branch ->superior rectus and levator palpebrae superioris
also
->inferior branch ->medial rectus, inferior rectus, inferior oblique mm

Autonomic (smooth muscle)
Motor nucleus in midbrain -> superior orbital fissure -> inferior branch -> ciliar ganglion -> ciliary muscle and circular muscle of iris

Question 15

image formation

Answer 15

1. reflection n bending of light by the lens and cornea
2. Accommodation (the change in the shape of the lens) when the eye is focusing on a close object, the lens become more spherical causing greater reflection of light rays (less than 20 feet)

Question 16

Ciliary muscle

Answer 16

controls the shape of lens

adjust the lens for near vision “accommodation’

Question 17

CN IV

Answer 17

Trochlear nerve
Motor eye movement superior oblique (look down and out)
Smallest cranial nerve
only on the arises from the posterior brain stem
trochlear nucleus ->superior orbital fissure -> superior oblique mm of eye ball

Question 18

CN VI

Answer 18

Abducens nerve (motor abducts the eye) in pons
Abducens nucleus ->superior orbital fissure -> lateral rectus muscle

Question 19

Superior oblique muscle

Answer 19

makes you look down and out

Question 20

Inferior oblique muscle

Answer 20

make you look up and out

Question 21

moves the eye towards the nose

Answer 21

Medial rectus

Question 22

moves eye away from the nose

Answer 22

lateral rectus

Question 23

moving eye up

Answer 23

superior rectus

Question 24

moves eye down

Answer 24

Inferior rectus

Question 25

makes you look down and out

Answer 25

Superior oblique rotates

Question 26

makes you look up and out

Answer 26

Inferior oblique

Question 27

CN III eye muscles

Answer 27

medial rectus superior rectus inferior rectus inferior oblique

Question 28

CN IV eye muscle

Answer 28

Superior oblique

Question 29

CN VI eye muscle

Answer 29

lateral rectus

Question 30

Damage to occulomotor

Answer 30

Strabismus : lazy eye, condition in which both eyes do not fix on the same object since one or both eyes may turn inword or outword Ptosis dilation of pupil movement of eyeball downward and outward on damaged side loss of accommodation for near vision diplopia (double vision)

Question 31

Damage to trochlear nerve

Answer 31

strabismus | diplopia

Question 32

damage to abducens

Answer 32

affected eyeball can't move laterally beyond midpoint and eyeball is usually directed medially

Question 33

CN V 3 branches

Answer 33

``` Trigeminal nerve (both motor and sensory) Sensory 3 branches 1. Ophthalmic V1 2. Maxillary V2 3. Mandibular V3 ```

Question 34

Ophthalamic nerve covers

Answer 34

``` sensory from skin over upper lid, cornea lacrimal glands upper nasal cavity side of nose forehead anterior half of scalp ```

Question 35

where does Ophthalmic pass to get trigeminal ganglion

Answer 35

superior orbital fissure

Question 36

Maxillary covers

Answer 36

``` sensory from mucosa of nose palate part of pharynx upper teeth upper lip lower eyelid ```

Question 37

where does maxillary pass through to join trigeminal ganglion

Answer 37

foramen rotundum

Question 38

Mandibular nerve covers

Answer 38

``` sensory from anterior 2/3 of tongue (not taste), cheek and its mucosa, lower teeth skin over mandible side of head anterior to ear mucosa of floor of mouth ```

Question 39

where does mandibular nerve pass to join trigeminal ganglion

Answer 39

foremen ovale

Question 40

What is the uniqueness of CNV?

Answer 40

Largest cranial nerve has both motor and sensory

Question 41

what does trigeminal motor nerve do? and where is it?

Answer 41

in mandibular branch supply mm of mastication these motor neurons mainly control chewing

Question 42

What is main pathology of Trigeminal nerve?

Answer 42

Trigeminal neuralgia (tic douloureaux) Sharp cutting intense pain that last for a few seconds to a minute is caused by anything that presses on the trigeminal nerve on its branches (V2 or V2 and V3 - lip, face, tongue) pain is within the nerve's distribution

Question 43

what are possible causes of trigeminal neuralgia

Answer 43

local compressions herpes zoster, vascular lesions, tumours demyelinating conditions with subsequent scarring (MS) ideopathic

Question 44

CN VII

Answer 44

facial nerve | sensory and motor and autonomic

Question 45

CNVII sensory route

Answer 45

Taste buds of anterior 2/3 of tongue ->stylomastoid foremen (temporal bone) -> genuculate ganglion -> pons -> thalamus ->gustatory area of cerebral cortex #43 also sensory axons from skin in ear canal (relay touch, pain, heat and cold)

Question 46

CN VII motor nerve route

Answer 46

nucleus in pons -> stylomastoid foremen -> fascial expression mm, stylohyoid mm, posterior digastric mm, stapedius mm

Question 47

CNVII autonomic nerve route

Answer 47

Superior salivatory nucleus -> 1. pterygopalatine ganglion ->lacrimal gland (tears), nasal gland (snot), palatine gland 2. Submandibular ganglion -> submandibular + sublingual glands

Question 48

CNVII pathology

Answer 48

Bell's palsy: paralysis of the muscles of facial expression on the same side as the lesion. unilateral weakness. onset can be rapid. If sensory and autonomic affected, the patient can't control lacrimation, decrease in salivation, can not taste on anterior 2/3 of tongue, heightened sensitivity of hearing. Sagging of face and eyelid

Question 49

how do you differentiate stroke and Bell's palsy?

Answer 49

Stroke affect lower half of facial muscles. The patient can control eye brow or can close eyes. The patient with Bell's palsy can not.