Unit 2 Flashcards
(107 cards)
1
Q
What is C.N. I?
A
Olfactory Nerve
2
Q
What are the neurons for the Olfactory nerve called?
A
Olfactory neurons
3
Q
Olfactory neurons are supported by “supporting cells” aka ________ cells.
A
bipolar
4
Q
Where are olfactory neurons found?
A
Olfactory epithelium lining the superior part of the nasal cavity.
5
Q
Olfactory neuron axons relay info where?
A
Olfactory bulb
6
Q
T or F: olfactory neuron axons are myelinated?
A
False. They are covered by Schwann cells
7
Q
What do olfactory nerves synapse on?
A
Dendrites of mitral cells
8
Q
What is formed at the synapse of an olfactory nerve on a mitral cell dendrite?
A
Synaptic glomeruli
9
Q
What is the secondary sensory neuron?-olfactory pathway
A
The mitral cell
10
Q
Mitral cell bodies are located where? (Where did olfactory neurons synapse on the mitral cell)
A
Olfactory bulb
11
Q
Mitral cells relay info ______ via the _________ ________.
A
posterior; olfactory tract
12
Q
The Olfactory Tract splits where?
A
At the anterior perforated substance.
13
Q
The olfactory tract splits into what?
A
Medial olfactory striae
lateral olfactory striae
14
Q
Do we. segregate smell?
A
No
15
Q
Where do medial stria fibers go?
A
The cross midline via anterior commissure and travel to opposite olfactory bulb.
16
Q
Where do lateral stria fibers go?
A
Primary Olfactory cortex; the periamygdaloid and perpiriform area, incuding uncus on medial side of temporal lobe
17
Q
Uncus = which broadman area?
A
34
18
Q
What are some clinical considerations of the olfactory nerve?
A
Loss of smell -anosmia
Skull fractures
CSF leakage
19
Q
What are the 3 layers of the eye?
A
From outside to inside
Fibrous tunic
Vascular tunic
Retina -10 layers
20
Q
The Fibrous layer of the eye is composed of what?
A
Cornea
Sclera
21
Q
What does the vascular layer of the eye consist of?
A
Ciiary body
Iris
Choroid
22
Q
What is the 1st layer of of the retina?
A
pigmented layer
23
Q
What is the 2nd layer of the retina?
A
photosensitive outer segments of rods and cones
24
Q
What is the 3rd layer of the retina?
A
external lining membrane
25
What is the 4th layer of the retina?
Outer nuclear layer. Contains rod and cone cell bodies.
26
What is the 5th later of the retina?
Outer plexiform layer; rods and cones synapse w/bipolar cells here
27
What is the 6th layer of the retina?
Inner nuclear layer containing cell bodies of bipolar cells
28
What is the 7th layer of the retina?
Inner Plexiform layer; bipolar cells synapse with ganglion cell here.
29
What is the 8th layer of the retina
Ganglion Cell layer; contains ganglion cell bodies
30
What is the 9th layer of the retina?
Nerve fiber layer; retinal ganglion cell axon. Fibers not myelinated
31
What is the 10th layer of the retina?
Internal limiting membrane. A glial boundary between retina and vitreous body.
32
The distal end of a photoreceptor is either _________ shaped or ________ shaped.
cylindrical (rod) or tapered (cone)
33
What recieves color information?
cones- 3 types (red, blue, green)
34
Cones require_____ to function.
light
35
Cones are concentrated where?
Fovea-center of retina
36
What senses light and dark?
rods
37
Are there rods in the fovea?
No. Just cones.
38
Where are rods located
around the fovea-periphery of retina
39
What is a clinical consideration of cones?
color blindness
40
Depolarized photoreceptors relay information to _______ ______ by synapsing in the _______ ______ ______.
bipolar cells; outer plexiform layer
41
What layer of the retina did we find bipolar cell bodies in?
Inner nucleus layer
42
Bipolar cells relay info to ganglion cells by synapsing on them where?
inner plexiform layer
43
Optic nerves enter the skull through the __________ _________.
Optic canal
44
When the optic nerves unite, they form the ________ _______.
Optic chiasma
45
Are nerve fiber layer axons myelinated?
No
46
Are optic nerve axons myelinated and why?
yes because they're coming from the CNS
47
What cells form myelin?
Oligodendrocytes
48
Fibers from the ______ side of the retina will cross at the optic chiasm?
medial (nasal) side
49
Fibers from the _____ side of the retina do NOT cross at the optic chiasm?
lateral (peripheral) side
50
How are optic tracts formed?
The medial and lateral fibers split
51
Optic tracts travel around the ________ _______.
Cerebral peduncle
52
Where do optic tracts synapse?
1 of 3 nuclei of termination
1. Lateral geniculate (MC)
2. Superior geniculate
3. pretectoral nucleus of midbrain
53
When optic fibers synapse on the lateral geniculate body, they are relayed where?
to the cerebral cortex in the occipital lobe (broadman area 17)
54
When optic fibers synapse on the superior colliculus where is info relayed?
The tectospinal tract
55
What 2 muscles are influenced by the tectospinal tract?
SCM
Trapezius
56
Optic fibers dealing with ______ ______ synapse in the pretectal nucleus of the midbrain.
light reflexes
57
Signs/Symptoms associated with a lesion of the optic nerve
Loss of depth perception
58
Signs/Symptoms associated with a lesion of the decussating fibers of the optic chiasma
loss of peripheral vision (tunnel vision)
59
Signs/Symptoms associated with a lesion of the optic tract?
Loss of vision from opposite side
60
What are some visual reflexes
Direct and consensual light reflexes
Accommodation reflex
Corneal reflex
Convergence
61
Testing the corneal reflex tests which cranial nerves?
C.N. V (trigeminal)
C.N. VII (Facial)
62
C.N. II is what?
Optic nerve
63
C.N. III is what?
Oculomotor nerve
64
What 2 extraocular muscles does the occulomotor nerve not supply?
Superior oblique
lateral rectus
65
Where are oculomotor nuclei located?
Periaqueductal gray matter
66
What part of the cerebral cortex sends axons to the oculomotor nuclei?
broadman area 8
67
What other areas send information to the oculomotor nuclei?
Superior colliculus
medial longitudianl fasciculus
68
LMN travel through red nucleus and exit CNS entering the PNS in the __________ ______.
interpeduncular fossa
69
When LMN (axon) enter PNS, they are covered by _______.
epineurium
70
When the LMN (axon) gets to the eye socket it splits into...
superior rami
inferior rami
71
The superior rami supplies what muscles?
superior rectus
levator palpebrae superioris
72
The inferior rami supplies what muscles?
medial-medial rectus
central-inferior rectus
lateral-inferior oblique
73
The accessory oculomotor nucleus also called what?
Ediger-Westphal nucleus
74
Ediger-Westphal nucleus contains what?
preganglionic parasympathetic neurons
75
Axons from the accessory oculomotor nucleus follow the _________ nerve and synapse in the _______ _______.
oculomotor
ciliary ganglion
76
Where is the ciliary ganglion located?
posterior to eyeball, 1 cm anterior to superior orbital fissure
77
What does the ciliary ganglion contain?
Postganglionic parasympathetic neurons. DUH! The parasympathetic preganglionic from the accessory oculomotor nucleus just synapsed on the ciliary ganglion so now they're postganglionic!
78
What do the postganglionic axons from the ciliary body go?
to the internal surface of the slcera to supply
ciliaris
pupillary constrictor aka sphincter pupillae
79
*Just so you know the ciliary ganglion also carries sympathetic and somatic sensory fibers.
They do not synapse in the ganglion. They just pass through.
80
What is C.N IV?
Trochlear Nerve
81
The trochlear nerve is somatic motor supply to what?
Superior Oblique muscle
82
The trochlear nucleus is located where?
The periaqueductal gray matter just caudal to the oculomotor nuclei
83
What part of the cerebral cortex sends axons tot he trochlear nucleus?
Broadman area 8
84
The trochlear nucleus also receives fiber from where?
Superior colliculus
Medial longitudinal colliculus
85
After leaving the CNS, the trochlear nerve curves around the _______ and continues within the lateral wall of the __________ _______.
brainstem
cavernous sinus
86
What plexus does the trochlear nerve communicate with?
Cavernous plexus (located in cavernous sinus)
87
What C.N. is named after a pulley?
Trochlear nerve
88
What is the only C.N. that crosses?
Trochlear nerve
89
What is the only C.N. on the posterior side of the brainstem?
C.N. IV
90
What is the smallest C.N.?
C.N. IV- Trochlear nerve
91
What is C.N. VI?
Abducens nerve
92
What muscle does the Abducens nerve supply?
Lateral rectus
93
Where is C.N. VI's nucleus?
caudal part of the pons at the rhomboid fossa
94
Axons from the trochlear nerve exit
a. anteriorly
b. posteriorly
posteriorly
95
Axons from the abducens nerve exit
a. anteriorly
b. posteriorly
anteriorly
96
Where does the adducens nerve receive information from?
Same as trochlear
Broadman area 8
superior colliculus
medial longitudinal colliculus
97
What is strabismus?
eyes not going in same direction
98
What is internal strabismus?
eye cross (converge)
99
What is external strabismus?
eyes are directed away from each other (diverge)
100
What is diplopia?
double vision; subjective bc can't really test it
101
What is it called when an eyelid droops due to weakness of levator palpebrae superioris?
Ptosis
102
Ptosis is commonly seen in patients with _________ syndrome.
Horner Syndrome
103
Oculomotor paralysis presents as what?
External Ophthalmoplegia-affected eye deviates down and out
Internal ophthalmoplegia would involve inability to constrict pupil as well as loss of light and accomodation reflexes
104
What are some possible etiologies of oculomotor paralysis?
uncal herniation
PCA aneurysms
diabetes
105
What is trochlear paralaysis?
-very rare
slight converging strabismus-inability to look down so difficulty going down stairs
106
What abducens paralysis?
*MOST COMMON*
Converging strabismus -inability to abduct eye
107
Internuclear Opthalmoplegia involves damage to what?
MLF
