Unit 2

Question 1

CN I found in olfactory epithelium lining ….

Answer 1

Superior part of nasal cavity

Sup. Nasal concha only, not middle or inf.

Question 2

T/F. Olfactory N are myelinated

Answer 2

F. Unmyelinated but they are covered by schwann cells

Question 3

Olfactory tract fibers split into medial and lateral olfactory striae at the ______________________.

Answer 3

Anterior perforated substance

Question 4

Medial stria fibers cross midline via the

Answer 4

Anterior commissure

Question 5

Lateral stria fibers carry info to the:

Answer 5

Primary olfactory cortex; on the medial aspect of the temporal lobe

Periamygdaloid and prepiriform area
–including the uncus (34) and entorhinal area (28)

Question 6

Alternative olfactory pathways

Answer 6

Terminal nerve & Vomeronasal nerve

Question 7

Terminal nerve pathway

Answer 7

From receptors on nasal septum (autonomic)

Question 8

Vomeronasal nerve pathway

Answer 8

Poorly developed in humans

Important for tracking prey

Question 9

3 layers of the eye

Answer 9

Outermost layer = fibrous tunic 
   Sclera, cornea
Middle layer = vascular tunic
   Ciliary body, iris, choroid
Innermost layer = retina 
   10 layers

Question 10

Retina layers

Answer 10

1. Pigmented layer
2. Photosensitive outer segments of rods and cones
3. External limiting membrane
4. Outer nuclear layer (rod/cone cell bodies)
5. Outer plexiform layer (synapse on bipolar cells)
6. Inner nuclear layer (bipolar cell bodies)
7. Inner plexiform layer (synapse on ganglion cells)
8. Ganglion cell layer (bodies)
9. Nerve fiber layer (retinal gang axons -not myelinated)
10. Internal limiting membrane (separates retina from vitreous body)

Question 11

Cones -3 types and where concentrated

Answer 11

Red, blue, green

More concentrated toward center of retina (fovea centralis = point of clearest vision)

Question 12

Ganglion cell axons (nerve fiber layer) -> 
\_\_\_\_\_\_\_\_\_ ->
Optic nerve ->
\_\_\_\_\_\_\_\_\_->
Optic chiasma

Answer 12

1. Optic disc

2. Optic canal

Question 13

Are optic nerve axons myelinated?

Answer 13

Yes.

Not myelinated inside eye. Axons leave eye at optic disc and become myelinated and form optic nerve.

Question 14

What cells form CNS myelin

Answer 14

Interfascicular oligodendrocytes

Question 15

In the optic chiasma, fibers from which side of the retina cross?

Answer 15

Medial (nasal) side cross

Lateral (peripheral) side do not cross

Question 16

Optic tract travels around cerebral peduncles and fibers synapse on 1 of 3 nuclei or termination:

Answer 16

1: Majority synapse in LATERAL GENICULATE BODY and are relayed to cerebral cortex in the occipital lobe (BDMN 17)
2: Superior colliculus - info relayed to tectospinal tract (SCM & Traps)
3: Pretectal nucleus of midbrain - fibers deal with light reflexes

Question 17

Visual Reflexes

Answer 17

Direct and Consensual light reflexes
Accommodation reflex
Corneal reflex
Convergence

Question 18

Direct and consensual light reflexes

Answer 18

Flashlight in eye to see both eyes contract

Question 19

Accommodation reflex

Answer 19

Switching focus

Question 20

Corneal reflex

Answer 20

Touch eye with cottonball

Question 21

Convergence

Answer 21

Cross eyes

Question 22

Oculomotor nuclei receive input from

Answer 22

1. BDMN 8
2. Superior colliculus
3. Medial longitudinal fasciculus

Question 23

Somatic nuclei of origin, located in periaqueductal gray matter

Answer 23

Oculomotor nuclei

Question 24

Oculomotor axoxs travel anteriorly through the Red nucleus and exit CNS in (apparent origin)

Answer 24

The interpeduncular fossa (into the cistern)

Question 25

Oculomotor nerve enters eye socket and splits into sup and inf rami, supplying ...

Answer 25

Superior ramus supplies superior rectus and levator palpebral superioris Inferior ramus splits into 3 branches: Medial branch supplies medial rectus Central branch supplies inferior rectus Lateral branch supplies inferior oblique

Question 26

Nerves leaving the ciliary gangion also carry sypathetic and somatic sensory fibers picked up from ...

Answer 26

The opthalmic nerve V1 passing through the ganglion without synapsing

Question 27

What parts of the brain send axons to the trochlear nucleus?

Answer 27

BDMN 8, Sup colliculus, and Medial longitudinal fasciculus

Question 28

Abducens nucleus is located...

Answer 28

In the caudal part of the pons, at the floor of the rhomboid fossa

Question 29

Abducens nerve receives info from

Answer 29

Same as CN III & IV BDMN 8, SC, MLF

Question 30

What is Strabismus

Answer 30

Eyes not pointing at the same thing

Question 31

Internal Strabismus

Answer 31

Eyes cross (converge)

Question 32

External strabismus

Answer 32

Eyes directed away from each other (diverge)

Question 33

Diplopia

Answer 33

Double vision

Question 34

Ptosis

Answer 34

Eyelid droops due to weakness of levator palpebrae superioris. CN III lesions may be the cause

Question 35

Oculomotor paralysis

Answer 35

External ophthalmopegia: 1. External strabismus; effected eye deviates down and out 2. Diplopia 3. Ptosis Internal ophthalmopegia: 1. Inability to constrict pupil 2. Loss of light reflex 3. Loss of accommodation reflex

Question 36

Etiologies of oculomotor paralysis

Answer 36

Uncal herniation, PCA anneurysm (post cerebral aneurysm) Diabetes

Question 37

Trochlear paralysis

Answer 37

Internal strabismus. Inability to look down (slight converging when looking down) Rare

Question 38

Abducens paralysis

Answer 38

MC Internal strabismus + displopia

Question 39

Internuclear ophthalmoplegia

Answer 39

Lesion to MLF Nystagmus when abducting eye

Question 40

Practice table 1 pg 183

Answer 40

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