Midterm 1 Flashcards
1
Q
Visual pathway order
A
retina, ON. chiasm, tract, lgn, radiations, striate cortex
2
Q
synapse 1
A
PR cell
- photon strikes photopigment
- photopigment splits- chemical rxn produce message
3
Q
synapse 2
A
bipolar cell
between PR and Gang
4
Q
synapse 3
A
ganglion cell
axons (optic nerve) –> optic chiasm –> optic tract
5
Q
synapse 4
A
LGN neuron
axon –> optic radiations
6
Q
which part of the ON is the longest?
A
intraorbital
7
Q
what part of the sphenoid does the ON go through?
A
lesser wing
8
Q
list the parts of the ON from shortest to longer
A
intraocular < intracanalicular < intracranial < intraorbitll
9
Q
how many fibers does the ON have
A
1-2.2 million
10
Q
what is the horizontal diameter of ONH
A
1.5 mm (1500um)
11
Q
what is the prelaminar part of the intraocular nerve
A
fascicles: sheats of astrocytes bundle ~1000 fibers per fascicle
12
Q
what is the laminar part of the intraocular nerve
A
within the lamina cribosa
13
Q
pathway of ganglion cells
A
ganglion cells from retina to LGN then become optic radiations
14
Q
what is the lamina cribosa
A
network of sclera fibers where the ON exits the eye
- if IOP goes up –> damage to the perforated nerve fibers that are in the sclera
15
Q
intraorbital portion of the ON diameter
A
3mm
16
Q
intraorbital portion of the ON postlaminar
A
Fascicles acquire a connective tissue sheath and become myelinated by oligodendrocytes
-surrounded by EOMs
17
Q
what is longer: globe or intraorbital
A
intraorbital is loner than the apex-apex measurement of the globe
18
Q
what is between the fascicle in the post laminar part of the ONH
A
glial tissue is between the fascicle
19
Q
why is the infraorbital portion of ON so long?
A
need wiggle room to look around
20
Q
where is myelination only located?
A
post laminar
21
Q
increases CSF affect on ON
A
push on it and it swells
22
Q
which layer of the meningeal sheath has a lot of BV
A
PIa- helps profuse parts of the ON
23
Q
what does glial tissue in the ON do
A
separates the nerve form the retina, choroid, sclera
24
Q
Intermediary tissue (of Kuhnt)
A
Glial tissue separating the retina
25
Border tissue (of Jacoby)
Glial tissue separating the choroid
26
Marginal tissue (of Elschnig)
Connective tissue continuous with the sclera
27
what is the ON inferior to?
olfactory tract and anterior cerebral artery
28
what is the ON superior and medial to?
ICA
29
what is the ON lateral to?
sphenoid body
30
what is the sheath of the optic nerve attached to
sheath of EOM
31
what two muscles does the optic nerve attach too?
MR and SR
32
what supplies the prelaminar and laminar portions of the ON
prepapillary choroidal network, unfenestrated
33
what supplies the postlaminar portion of the ON
Ophthalmic artery
Central retinal artery
Pial vessels
34
what supplies the intracranial
Ophthalmic artery
Anterior cerebral artery
Anterior communicating artery
Internal carotid artery
35
what does the circle of willis surrond
chiasm
36
what is the chiasm posterior and interior to
anterior cerebral and communicating arteries
37
what is the chiasm medial to
internal carotid arteries
38
what is the chiasm inferior to
3rd v
39
what is the chiasm superior to
pituitary gland
40
what supplies blood to the chiasm from the superior network
Anterior communicating artery
| Anterior cerebral artery
41
what supplies blood to the chiasm from the inferior network
Posterior communicating artery
Posterior cerebral artery
Internal carotid artery
42
what is a flattened cylindrical band of ganglion fibers from the chiasm to LGN
optic tract
43
where to 90% of the fibers from the optic tract go
LGN
44
where do 10% of the fibers from the optic tract go
Pretectal area
Superior colliculus
Hypothalamus
45
what is lateral to the optic tract
cerebral peduncle
46
what is parallel to the optic tract
posterior cerebral artery
47
what is inferior to the optic tract
globus pallidus
48
what supplies blood to the optic tract
Anterior choroidal
| Middle cerebral
49
where is the LGN located
dorsolateral portion of the pulvinar thalamus
50
where do retinal axons terminate
LGN
51
magnocellular layer
```
layer 1-2
large
motion/ low spatial frequency
upper/dorsal stream
where/how
4ca
```
52
parvocellular layer
```
layers 3-6
small
high contrast, detail, high spatial frequency
ventral stream
what
4cb
```
53
koniocellular layers
dispersed - dust like- small- color vision and high frequency
54
what is the function of the LGN
visual processing
- Ensures the most important information is sent to the visual cortex
- Has a pathway to the visual cortex and other cortical areas
- Has a pathway from the visual cortex
55
what is medial to the lgn
internal capsule and inferior horn of the lateral ventricle
56
what is lateral to the lgn
medial geniculate nucleus
57
what supplies the LGN
Anterior choroidal artery
| Posterior choroidal artery
58
what is another name for optic radiations
Geniculocalcarine Tract
59
what part of the brain do the optic radiations pass through
parietal and temporal lobe
60
what is lateral to the optic radiations
inferior horn of the lateral ventricle
61
what supplies the anterior radiations
anterior choroidal artery
62
what supplies the middle radiations
deep optic branch of the middle cerebral artery
63
what supplies the posterior radiations
calcarine branch of the posterior cerebral artery
64
what are other names for the primary visual cortex
striate cortex
Brodmann Area 17
V1
65
where is the primary visual cortex located
- Medial portion of the occipital lobe
| - Line of Gennari runs near the calcarine fissure
66
what separates the cuneus gyrus and lingual gyrus
- Calcarine fissure
| - Intersects the parietooccipital sulcus
67
function of the primary visual cortex
Process visual information
| Integration of binocular information
68
visual cortex vertical organization
- Ocular dominance columns
- Columns for stimulus orientation
- Responds to the direction of light
69
what eye does 146 to go to
opposite
70
what eye does 235 go to
same side
71
blood supply to the primary visual cortex
Calcarine branch of the posterior cerebral artery
72
Visual association areas other names
Brodmann areas 18, 19 now referred to as V2, V3, V4, V5
73
Visual association areas functions
Functions as storage for visual patterns and recall
74
striate connections to the superior collculus
fixation and saccades
75
striate connections to the hypothalamus
Circadian rhythm
76
striate connections to frontal eye fields
Voluntary and reflexive binocular eye movements
77
striate connections to
| nucleus of the optic tract
Optokinetic nystagmus (OKN)
78
retinal nerve fiber layer
-Ganglion cell axons
- Papillomacular bundle
- Horizontal raphe
79
where do macular fibers move towards
the center
80
where do the superior temporal fibers exit to
medial optic tract
81
where do the superior nasal fibers cross
cross to contralateral, medial optic tract
| -posterior knees of wilbrand
82
inferior temporal fibers exit to the
lateral optic tract
83
where do inferior nasal fibers cross
contralateral lateral optic tract
| -anterior knees of wilbrand
84
nasal fibers cross to
contralateral eye
85
what two fibers go into eye
ipsilateral temporal fibers and contralateral nasal fibers
86
what fibers are seen in the optic tract
Superior peripheral fibers
Inferior peripheral fibers
Macular fibers are in the middle
87
what fibers are seen in the LGN
Superior peripheral fibers
Inferior peripheral fibers
Macular fibers
88
optic radiation superior fibers
Parietal lobe
89
optic radiations Inferior fibers
Temporal lobe
| - meyers loop
90
Visual cortex Superior fibers
cuneus gyrus
91
Visual cortex Inferior fibers
lingual gyrus
92
where are the macular fibers in the visual cortex
run posterior
93
retinal defects: temporal field is imaged in the
nasal retina
94
retinal defects: superior field is imaged in the
inferior retina
95
Right side of visual field imaged in ____ retina of the right eye and ____ retina in the left eye
1. nasal
| 2. temporal
96
characteristics of retinal defects
unilateral, irregular shaped, can cross the horizontal and vertical midlines
97
visual field of retinal nerve fiber layer
- Group of ganglion cells
- Arcuate scotoma or nasal step
- Horizontal midline typically respected
98
visual field of optic nerive
Central or centrocecal defect
With compression, macular fibers are often affected first
(+)APD, afferent pupillary defect - defect in ganglion cell fibers
99
visual field of chiasm
Optic Chiasm
First place where a single lesion will affect both eyes
Nasal fibers cross the midline
100
VF of pituitary gland adenoma
Bitemporal hemianopia
101
what is the pituitary gland inferior to
optic chiasm
102
Involves both lateral sides of the chiasm
Binasal hemianopia
103
Anterior Junction Syndrome
- Compression of the optic nerve at its junction with the chiasm
- Central defect in ipsilateral eye
- “pie in the sky” in the contralateral eye
104
Post-chiasmal lesions
Damage affects the contralateral field
- Homonymous hemianopia
- Incongruent - closer to chiasm
- Congruent - further from the chiasm
- Vertical midline respected
105
Optic tract: Right visual field carried in __ optic tract
left
106
Optic tract: Left visual field carried in __optic tract
right
107
when are pupils affected in the optic tract
if lesion is in the anterior 2/3 of the tract
108
what type of vfl does lgn have
Homonymous loss
109
what type of vfl do optic radiations have
Likely a quadranopsia
110
Visual cortex
| visual field
- Congruent homonymous hemianopia
- Visual acuity usually not affected
- Macular sparing vs macular splitting
111
Temporal crescent
Portion of the peripheral field without a counterpart in the nasal field of the other eye
-Located very _anterior__ in the visual cortex
112
visual field for prechiasmal
monocular
113
visual field for post chiasmal
binocular
114
where is the blind spot located in visual field
temporal
115
Homonymous
- Both eyes show a loss
- Nasal field of one eye and temporal field of the other eye
- Respects the vertical midline
116
Hemianopia or Hemianopsia
- Homonymous defect extends past the 180th meridian
- Involves half of the visual field
- Respects the vertical midline
- “homonymous hemianopia”
117
where does the lesion occur on a right homonymous hemianopsia
lesion occurred on left side
118
Quadranopia or quadranopsia
- Corresponding quadrant of both eyes are affected
| - Respects the vertical midline
119
lesion of: Homonymous superior right quadranopsia congruent
Lesion on left side of brain- temporal lobe
120
Congruent
Defects are symmetric
121
Incongruent
Defects are asymmetric
| anterior probs at optic tract
122
Heteronymous
Fields of both eyes show a loss on opposite sides
Bitemporal
Binasal
123
Altitudinal
- Upper or lower half of the field affected
- Respects the horizontal midline
- Unilateral
- Bilateral
- Damage to the upper or lower calcarine fissure of both eyes
124
Scotomas
Island defect surrounded by “seeing field”
125
Paracentral scotoma
Does not affect fixation
126
Pericentral ring
- Does not affect fixation
| - Makes an annular pattern
127
Cecal
Enlarged blind spot
128
Centrocecal / cecocentral
Includes fixation and the blind spot
129
Nerve fiber bundle defects
| Nasal step
Defects on the horizontal midline nasally >15 degrees away from central fixation
130
Arcuate scotoma
Complete or incomplete/partial
| Double arcuate
131
Temporal wedge
A small defect temporal to the blind spot
132
when does the neural groove and neural folds form
day 18-21
| + last time we see endoderm
133
when is the embryonic plate formed
week 3
134
what does the neural ectoderm form
brain + spinal cord
135
how are optic pits formed
indentations from the surface of the neural tube
136
what does the optic stalk become
optic nerve
137
how does the optic cup form
indents inferially + slightly nasal
| - optic pit --> optic vesicle --> optic cup
138
when does the fetal fissure begin to fuse
week 5
| starts at center --> goes anteriorly + posterially
139
when is the closure of the fetal fissure complete
week 7
140
coloboma defintion
incomplete closure of the fetal fissure
| -always inferially and slightly nasal
141
coloboma: keyhole pupil
iris, usually bilateral, light sensitivity
142
coloboma: retina
- no RPE, can see straight through sclera, unilateral, can have no light perception
143
how does the optic stalk form
tissue joining the vesicle to the neural tube constrict
144
what muscles come from the neural tissue
dilator + sphincter
145
order of structures in optic cup (outer to inner)
iris, cb, retina
146
outer layer of optic cup epitheliums (outer to inner)
anterior iris epithelium w/ dilator + sphincter, outer pigmented cb epithelium, RPE
147
inner layer of optic cup epitheliums (outer to inner)
poster iris epithelium, inner non pigmented cb epithelium, neural retina
148
when does the lens placode form
day 27
149
what is induction
formation of some structures depend on interactions among other tissues
need optic vesicle and surface ectoderm to form lens placode
150
micropthalmos
small eyeball- neither optic cup or lens develop correctly blind eye- unilateral; small globe, need close contact for optic cup + lens to develop
151
when does the lens vesicle separate form the surface ectoderm
day 33
| clinical importance forms capsule
152
embryonic nucleus
posterior epithelium elongates to fill in the lumen
153
fetal nucleus
everything after embryonic nucleus up to when its born
- contains all fibers formed before birth
- mitosis at equator
154
y sutures
tells us where embryonic nucleus is
| -outside= fetal + adult nucleus
155
y upright and inverted
```
upright= anterior
inverted= posterior
```
156
congenital cataract
appearance tells us where it is located
- congenital= center- early in development
- usually devastating in center
- y suture cataract if it forms a bit later
- --- doesnt cause problems, fetal nucleus cataract
157
when does the hyaloid arterial system begin
week 5
158
what is the hyaloid artery a branch of
ICA
159
what hyaloid artery enters ___ through the _____
optic cup, fetal fissure
160
what lies within in the fetal fissure
bv, fills up vitreous cavity
| formed from mesanchyme
161
mesanchyme
combination of neural crest + mesoderm; CT of globe
162
when does atrophy of hyaloid arterial system begin
month four
| - starts to reabsorb,
163
when does the central retinal artery form
month 4
| - primitive retinal vessels emerge from the ON
164
when is the hyaloid arterial system totally reabsorbed
by birth
| - goal is to supply blood + nutrients to the lens
165
bergmeister papilla
posterior remnant of on lens
| glial tissue persists at the ONH
166
mittendorf dot
anterior remnant of lens
- pinpoint area of tissue on the posterior lens
- opaque, black area
167
where does the CRA develop from
portion of the hyaloid artery
168
when do retinal bv fully form
3 months after 3
169
retinopathy of prematurity
baby born early, put in o2 chamber
- retinal bv don't develop because there is no need
- after taken out of chamber you get neo-vascularization- retinal detachment
- now they gradually take out to allow bv growth
170
what is the retina formed from
optic cup
171
when does RPE pigmentation in the outer later of the opti cup form
weeks 3-4
172
when do the inner layer of the optic cup form two zones
week 4-6
173
where is the proliferative zone located
outer, germinative zone, closest to RPE, has cell bodies
174
where is the marginal zone of his located
inner, anuclear
175
what does the BM of the inner layer of the optic cup become
internal limiting membrane
176
when does the migration of the proliferative zone occur
week 7
177
what four layers emerge from the migration of the proliferative zone
outer neuroblastic layer, transient later of chievitz, inner neuroblastic layer, marginal zone of his
178
what layers does the outer neuroblastic layer become
PR + bipolar + horizontal
179
what layers does the inner neuroblastic layer become
muller, amacrine, ganglion
180
when does differentiation of the neuroretinal cells occur
month 3
181
what is crucial in the formation of the fovea and macula
displacement of the GCL and INL
182
when doe ganglion cells and INL move to the peripheral macula
week 7
183
a birth is there still ganglion cells and INL present?
yes thin layer in fovea
184
when does complete displacement of ganglion cells and INL from fovea occur
4 months after birth
| -
185
where are the only cell bodies in the macula
ONL
186
when can you see 20/20
age 5
187
where/when do cones migrate
4-5y after birth
| towards the center- so many cones that they get squished and look like rods
188
ocular albinism
isolated to eye,
| shining light to eye- coming out everywhere- RPE usually stops this, fovea doesn't develop
189
fovea aphasia
underdeveloped macula + foveal depresstion
190
horinzontal raphe
ganglion cell axons wrap around mac bundles to get back to the optic disk to get to the brain- temporary
191
how does VF look if damage to NFL
respects horizontal midline
192
when does ganglion cell axon myelination begin
month 5 when axon reach LGN
193
what are ganglion cell axons myelinated with
oligodendrites
194
when does myelination reach chiasm
month 6
195
when does myelination reach lamina cribosa
1-3 months after birth
196
when does corneal formation begin
day 33
197
what gives rise to the corneal epithelium
surface ectoderm
198
what gives rise to corneal stroma and endothelium
neural crest
199
corneal characteristics at birth
55D, circular and steep- eye is smaller- need steeper to refract light
200
when does corneal curvature decrease
44D, 6 months after birth
201
what gives rise to the sclera
neural crest cells
| mesanchyme surrounding --> comes around --> forms sclera
202
what gives rise to the choroid
neural crest cells
| - has to be in contact with RPE to develop properly
203
what does neural ectoderm give rise to in CB
outer and inner epithelium of CB
204
what does neural crest cells give rise to in CB
to the ciliary muscle + stroma
205
when does the tip of the optic cup elongate between the lens and the cornea
month 3
206
what does neural ectoderm give rise to in the iris
anterior+ posterior iris epi, dilator + sphincter
207
what does neural crest cells give rise to in the iris stroma
stroma
208
what gives rise to the anterior border layer
mesanchyme;
| area between cornea + lens
209
how long can the iris darken
6 months after birth
210
aniridia
absense of iris: eye is dilated all the time;
211
increase in depth of focus means
decrease in pupil size
212
when does a pupillary membrane form between the lens and cornea
month 3
| bvs help supply blood to the cornea
213
when is the pupillary membrane completely broken
month 8.5
| vessels fragmented + disappear
214
PPM
strings common
remnant of pupillary membrane
17-32% of population have this
215
Primary Vitreous
old dengenerating tissue - hyaloid tissue
| retina + lens fiber
216
secondary vitreous
encloses the primary vitreous forming cloquet's (aka hyaloid) canal
- theoretical
- secondary vitreous formed around this
- forms attachments at vitreous base and hyaloid capsular ligament (weiger's ligament)
217
when do folds of surface ectoderm filled with ____ grow toward eachother
mesenchyme; month 2
218
when do eyelid margins fuse
month 3
219
when do eyelids separate
month 5-6
220
what does surface ectorderm in the ocular adnexa give rise to
- skin + conj epithelium, hair follicles + cilia, meibomian glands, zeis glands, glands of moll
221
what does mesenchyme in the ocular adnexa give rise to
tarsal plate, orbicularis, levator, tarsal muscle of muller,
222
what do neural crest cells give rise to in the orbit
orbital fat and CT
223
what does mesenchyme in the orbit give rise to
EOMs
224
when is the lacrimal system fully develop
3-4 y
225
what does the surface ectoderm give rise to in the lacrimal system
nasolacrimal drainage
226
what do the bones of the skull form
anterior and superior portion
| forms anterior cranial fossa
227
what does the occipital bone form
posterior fossa
| occipital lobe + cerebellum
228
inion
external occipital protuberane
229
-visual evoked potential electrode
measure electric potential that vision creates
| -used if cant respond to visual acuity or if someone is faking VF loss
230
where should the VEP be placed
3cm above inion- visual cortex is here
231
squamous portion of the temporal bone
anteriorly, makes of most of the lateral portion
232
petrous portion of the temporal bone
houses most of the middler and inner ear system
233
CN6 Palsy with papilledema
- 90 degree turn to go to cav sin
- with increase IOP = increase fluid pushes brainstem down
- stretches CN6 -double vision -papilledema
234
what does the CN6 go over
petrous portion of the temporal bone
235
body of sphenoid
along midline, forms the sella turica
236
lesser wing
anterior, superior, smaller
237
what is the optic canal formed by
hole between body and lesser wing
238
what foramen lies within the lesser wing
optic foramen
239
greater wing
projects more laterally
240
foramens in the greater wing
rotundum, ovale, spinosum
241
foramen rotundum
maxillary nerve CN5 V3
242
foramen ovale
mandibular branch V2
243
foramen spinosum
middle meningeal artery
244
superior orbital fissure
v1 goes through this,
| holds everything in cav sin (3.4,6)
245
gap between the greater and lesser wing
SOF
246
horizontal cribriform plate
olfactory nerve comes through here and goes to brain
247
ethmoid air cells
lightens skull, forms ethmoid sinuses
248
orbital bones
frontal, maxillary, zygomatic, sphenoid, ethmoid, lacrimal, palative
249
roof of orbit
frontal bone, lesser wing of sphenoid
250
roof landmarks
fossa of lacrimal gland, trochlea
251
what does the superior oblique muscle go through
trochlea
252
supraorbital notch
supraorbital vessels + nerves
253
supracochlear notch
supracochlear vessels + nerves
254
floor bones
max (medial), zygo (lateral), palatine (posterior)
255
floor landmarks
- inferior orbital fissure- btwn orbit and pterygopalatine + temp fossa
- infraorbital groove- canal in max bone
- infraorbital foramen - v2 (max nerve)
256
blow out fracture
hit in the eye
- fracture of inferior floor- bone is broken
- compresses globe, weaker due to canal, groove
- double vision- numbness because of nerve, swelling, ecchymosis- black eye
257
lateral wall bones
zygo, greater wing
258
lateral wall landmarks
superior orbital fissure
| inferior orbital fissure
259
medial wall bones
frontal process of maxillary, lacrimal, orbital plate of ethmoid bone (majority, thinnest), body of spenoid
260
lamina papyracea
paper thin - ethmoid
261
medial wall landmarks
fossa of lac sac- anterior crest- max bone, poster crest: lacrimal
-naslac canal- tear drainage
262
orbital dimensions
4 cm horizontal, 3.5 cm vertical, 4.5 deeep
263
common tendinous ring aka annules of zinn and ocularmotor foramen
- circular band of CT
| - origin of rectus muscle
264
through the optic canal and common tendinous ring
optic nerve goes through optic canal --> through ring --> to orbit, ophthalmic artery goes through here
265
ophthalmic artery
all of circulation to eye ball and surrounding
266
through superior orbital fissure above the common tendinous ring
lacrimal nerve, trigeminal nerve, trochlear nerve, superior ophthalmic vein (drains majority of globe)
267
through the SOF and common tendinous ring
cn3, nasociliary nerve (CN5)- sensory, cn6
268
through the IOF below the common tendinous ring
infraorbital nerve, infraorbital artery + vein
269
sinuses
air filled cavities within four of the bones surrounding the orbit
270
frontal sinus
above the frontal bone
271
ethmoid sinus
medial to eyes, one of the thinnest- serious infection
272
sphenoid sinus
medial to eye, more posterior, within body of sphenoid, can surround optic canal
273
maxillary sinus
inferior to eyeball, largest, blowout fracture- orbital tissue into maxillary sinus
274
orbital cellulitis
- infection in orbit
- thin wall ethmoid sinuses-> ethmoid- eats away through orbit
- very serious infection
- direct pathway from __ to __ to brian
- proptosis, swollen, 30% die, hospital right away, double vision is telling factor, fever
275
orbital connective tissue
keeps eye in place w/ infections, lines separates and anchors orbital structures
276
periorbita
covers the bone
| thickened at apex- forms annules of zinn, carries blood + nerves to the bone
277
orbital septum
continuos with periorbita @ margins of bone
- 360 degree rim of orbit- tarsal plate
-keeps orbital fat in place
- prevents infection- from eyelis and back
- behind lac sac to prevent infection
behind glands of eyelids too
278
preseptal cellulitis
infront of orbital septum
not as serious as orbital septum- away from brain
due to eyelid infection- mostly hordeoulum- can burst inside eyelid and cause infection in it
-if breaks through orbital septum can cause orbital cellulitis
treat with antibiotics
no double vision, proptosis, no fever
279
muscle pulleys/ check ligaments
ct that stabilize muscle, prevents over acton of muscles, tissue to connect to bone
280
suspensory ligament of lockwood
hammack like support so globe doesnt fall
| inferior support
281
tenon capsule
surrounds globe itself- all way around
barrier to infection getting into globe- into eyeball
between conj and episclera
acts as attachment to EOMs to eye (globe)
stabilization
282
orbital fat
adipose tissue- fills in everything else in orbit
