Embryology Flashcards

(90 cards)

1
Q

what fibers are included in the fetal nucleus

A

contains all fibers before birth

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2
Q

what type of fibers are in the fetal nucleus

A

secondary fibers

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3
Q

how does the embryonic nucleus form?

A

posterior epi elongates to fill the lumen

formation of the lens bow

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4
Q

what type of fibers are in the embryonic nucleus?

A

primary lens fibers

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5
Q

when do the eyelids fuse and separate?

A

fuse: month 3
separate: month 5-6

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6
Q

lacrimal system: surface ectoderm

A

nasolacrimal drainage system

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7
Q

what is a coloboma?

A

incomplete closure of fetal fissure in the inferior and nasal aspect

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8
Q

when does the optic cup elongates between the lens + cornea

A

month 3

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9
Q

what structures can be involved in an coloboma

A

optic disc, iris, retina, cb, optic nerve

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10
Q

what structures in the iris are formed from neural ectoderm

A

anterior + posterior iris epi

dilator + sphincter muscle

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11
Q

bergmeister papilla

A

glial tissue persists at ONH

  • posterior remnant on lens
  • remnants of the fetal hyaloid system
  • posterior remnant of the hyaloid system
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12
Q

what structure is the retina formed from?

A

optic cup

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13
Q

Mittendorf dot

A

small, circular opacity on the posterior lens capsule, classically nasal in location, which represents the anterior attachment of the hyaloid artery

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14
Q

what is the GCL + INL like at birth?

A

still thin layer across fovea

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15
Q

when are the GCL + INL completely displaced from fovea

A

4 months post birth

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16
Q

what is corneal curvature

A
  • circular + steep (55D) @ birth

- decreases to 40D 6mo after birth

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17
Q

what is the first step in corneal development and when does it happen

A

day 33- corneal epi from surface ectoderm

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18
Q

aniridia

A

absence of iris- altered depth of focus

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19
Q

iris: neural crest cells

A

iris stroma

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20
Q

when does myelination reach the chiasm? lamina cribosa?

A

chiasm: 6 mo

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21
Q

what is the horizontal raphe

A

wraps around mac bundles to get back to optic disc –> brain
-horizontal raphe is temporary

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22
Q

when does myelination reach lamina cribosa?

A

LC: 1-3 mo after birth

-visual implications, foveal displacement, cone development, myelination

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23
Q

where does myelination travel from and to

A

from brain –> eye

LGN –> lamina cribosa

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24
Q

horizontal raphe fibers

A

inferior and superior fibers dont cross

if damage to NFL - VD respects midline

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25
inferior damage in horizontal raphe
superior VFD
26
where does maturation of PR occur
fovea + macula
27
what is in hollow eye ball
empty space filled w/ CSF | continuous w/ 3rd V
28
mesenchyme iris
anterior border layer
29
how long can iris darken
6 mo after birth | bc --> blood to cornea
30
hyaloid artery system process
hyaloid artery (ICA branch) enters optic cup through fetal fissure, filling the vitreous cavity, supplies nutrients to lens
31
neural plate- what happens at week 3
thickening of ectoderm on the dorsal side
32
when do cones migrate towards center
4-5 yrs after birth | 20/20 at age 5
33
what does neural plate gives rise to
CNS + ocular structures
34
what gives rise to hyaloid artery system
mesenchyme ( CT of globe)- neural crest and/or mesoderm
35
hyaloid artery system: 4th month
atrophy- totally reabsorbed by birth- to supply to nutrients to lens
36
eyelids: surface ectoderm
- skin + conj epi - hair follicles + cilia - meibomian glands - zeis glands - glands of moll
37
when/where does CRA develop from?
month 4 from HAR
38
when does CRA fully develop?
3mo after birth
39
what happens to RPE in week 3-4
RPE pigmentation seen in outer later of optic cup
40
when does optic pit form into the optic cup
day 25
41
neural crest cells do what
tissue that differentiates
42
what are optic pits
indentations form on the surface of the neural tube
43
when do INL and GCL begin to move to peripheral macula
month 7
44
when does pupillary membrane form between lens + cornea and why
month 3
45
when does pupillary membrane completely break off
month 8.5
46
when do the optic pits form
day 22
47
coloboma: key hole pupil
bilateral- light sensitive
48
orbit: neural crest cells
orbit fat + CT
49
when does neural retinal cells differentiate
month 3
50
what is the potential space between the neural retina + RPE
site of retinal detachment | NR + retina separated
51
what is micropthalmos
small globe; incomplete development of optic cup + lens (lack of induction) likely a blind eye
52
when does the lens placode form and how
day 27 | induction: formation of some structures depends on interactions among other tissues
53
what week is the embryonic plate formed by
week 3
54
what does the lens vesicle form and how
day 33 | forms once it separates form surface ectoderm
55
persistent pupillary membrane
remains attached to lens or free floating | very common 17-32%
56
what is primary vitreous
degenerating tissue from hyaloid system + fibers ret + lens
57
when does myelination begin and why
months 5 - when axons reach the LGN
58
what is secondary vitreous
encloses primary vitreous forming cloquets canals | forms attachment at vitreous base + hyaloid capsular ligament
59
when does the fetal fissure begin to fuse
week 5 (goes anteriorly --> posteriorly)
60
when does fetal fissure close
week 7
61
what gives rise to the lens capsule
BM
62
what type of cell gives rise to sclera
neural crest cells | goes around optic cup until reaches ON
63
retina coloboma
no RPE can see straight through sclera unilateral can have no light perception
64
continuous | outer --> ? --> CB --> inner
anterior epithelium w/ dilator + sphincter muscle --> CB --> posterior epi
65
continuous | outer --> ? --> IRIS --> inner
anterior pigmented epi --> CB --> inner non-pig epi
66
continuous | outer --> ? --> RETINA --> inner
RPE --> retina --> neural retina
67
how is the optic stalk made
tissue joining the vesicle to the neural tube constricts
68
what structures are needed for the lens placode to develop
optic vesicle and surface ectoderm
69
y suture cataract
allows lines of suture, very common can see around- not visually important can use location for timeline of development
70
retinopathy of prematurity
baby born early- put in 02 chamber retinal bv dont develop bc no need after taken out - you get neovascularization- ret detach now they gradually take out to complete growth
71
what happens in neural retina at week 7
migration of the proliferative zone rpe --> outer neuroblastic layer (2 cells) --> transient later chievits --> inner neuroblastic layer (2 cells) --> marginal zone of His --> vitreous
72
eyelids mesenchyme
tarsal plate, obicularis, tarsal plate muller - rare for muscles to be formed by neural cells - sphincter + dilator is an exception
73
day 22- neural
neural folds fuse to form neural tube --> brain + spinal cord brain = neural ectoderm
74
ocular albinism
reduced pigmentation of ocular structure, no foveal depression, BVA: 20/30 -underdeveloped macula from lack of signals from RPE
75
what 2 zones does the neural retina form
proliferative (germinative) zone: outer closest to RPE, has cell bodies ( 4 cells) marginal zone of His (inner, anuclear)
76
CB: neural crest
ciliary muscle, ciliary stroma
77
CB: neural ectoderm
outer pigment epi, inner non-pig epi
78
what gives rise to choroid and what structures needed
neural crest cells | needs RPE contact or proper development
79
when does hyaloid artery system begin
week 5
80
neural crest cells: cornea
cornea stroma + endo
81
when does development of neural retina
week 4-6 cells of inner layer of optic cup form 2 zones
82
congenital cataract | embryonic cataract
formation in embryonic nucleus | devasting to vision, surgery to avoid amblyopia
83
when do neural retinal cells differential
month 3
84
when does the neural groove and neural folds form
day 18-21
85
lacrimal gland development
not fully formed at birth | not developed until 3-4yo
86
when/where first place to see pigment in body and when
RPE at week 3-4
87
when does optic pit turn into optic cup
day 25
88
optic stalk -->
optic nerve
89
fetal nucleus
anterior: upright y posterior: inverted y cells go posteriorly + anteriorly until they come together at midline
90
when does folds of surface ectoderm + mesenchyme grow together
month 2