Ocular: Embryology Flashcards
1
Q
Developing ocular structures induce the development of other structures in a process known as __________
A
Induction
2
Q
Around the 3rd week of development, the embryonic plate forms and consists of two layers:
A
Ectoderm
Endoderm
3
Q
What is the central depression that forms on the ectodermal surface called?
A
Primitive streak
4
Q
Mesoderm forms and divides the embryonic plate into 3 primary germ layers:
A
Ectoderm
Mesoderm
Endoderm
5
Q
Ocular structures develop from two out of three primary germ layers: which ones?
A
Ectoderm and mesodermal
6
Q
The ectoderm thickens and forms what?
A
Neural plate
7
Q
The neural plate gives rise to the ?
A
CNS and Eye
8
Q
A longitudinal groove that forms in the center of the neural plate
A
Neural groove
9
Q
Neural crest cells and mesoderm are referred to as _____________
A
Mesenchyme
10
Q
Failure of neural tube to close posteriorly results in __________
A
Spina Bifida
11
Q
Failure of neural tube to close anteriorly results in ___________
A
Anencephaly
12
Q
Optic sulci are the first stage of development of the _______
A
Eye
13
Q
The optic sulci deepen and form a hollow diverticulum known as ___________
A
Optic vesicles
14
Q
Proximal portion of optic vesicle near the forebrain constricts to form the _________
A
Optic stalk
15
Q
Invagination of the inferior surface of the optic stalk causes the distal part of the optic vesicle to invaginate, forming a __________ layered cup which is called the ____________
A
Double-layered cup which is called the optic cup
16
Q
After the formation of the optic cup, what will infiltrate the optic tissue and move toward the cavity of the optic cup?
A
Mesenchyme and hyaloid artery and vein
17
Q
The optic cup consists of two layers
A
Outer layer
Inner layer
18
Q
Optic cup: The inner surface of the _________ and ________ layer face each other
A
Inner and outer
19
Q
The cells of inner and outer layers of the optic cup are arranged _________ to _________
A
Apex to apex
20
Q
What explains the apex to apex arrangement between the RPE and neural retina, anterior and posterior iris pigment epithelium, and non-pigmented and pigmented ciliary epithelium?
A
The face the cells of inner and outer layers of the optic cup are arranged apex to apex
21
Q
The inner and outer layers of the optic cup are separated briefly by the _________ space
A
Intraretinal space
22
Q
3 structures derived from the inner layer of the optic cup
A
Neural retina
NPCE
Iris posterior pigment epithelium
23
Q
3 structures derived from the outer layer of the optic cup
A
RPE
PCE
Iris anterior myoepithelium
24
Q
Contact between the optic vesicle and surface ectoderm induces formation of the __________
A
Lens placode
25
Lens Placode invaginates to form
lens pit
26
Lens pit further deepens and forms a hollow vesicle, the ____________
Lens vesicle
27
What two muscles arise from the neuroectoderm?
Iris dilator muscle and iris sphincter muscle
28
Posterior epithelial cells of the lens become packed with crystallins and elongate to form the _____________ fibers which form the ___________ nucleus.
Primary lens fibers which form the embryonic nucleus
## Footnote
Explains why the fully formed lens lacks a posterior epithelium
29
As apices of the primary lens fibers fill in the hollow lens cavity, their nuclei move anteriorly within the cell and form a pattern known as the _____________
Nuclear lens bow
30
The anterior lens epithelium at the equator undergoes mitotic division throughout life and gives rise to _______________
Secondary lens fibers
31
Secondary lens fibers do not completely extend from the anterior to posterior surface. Instead what occurs?
Basal and apical ends of secondary lens fibers are in apposition at distinct sites known as fetal Y sutures
32
In the anterior part of the fetal nucleus, the Y suture is situated _________
Upright
33
In the posterior part of the fetal nucleus, the Y suture is situated __________
Inverted
34
The fetal nucleus continues to develop until _________
Birth
35
Secondary lens fibers that are laid down between birth and sexual maturity reside in the ___________
Adult nucleus
36
What contains secondary lens fibers that have an intact cell nucleus?
Lens cortex
37
Encapsulating the entire lens is the basal lamina, which is laid down by the ____________. It gradually thickens and becomes the __________
Lens epithelium
Lens capsule
38
External to the lens capsule is a vascular capsule called the _________________
Tunica vasulosa lentis
39
The tunica vasculosa lentis is formed by the ______________
Hyaloid vasculature that entered the developing eye via the optic fissure
40
Vascular shell supplies nutrients to the _____________
Developing lens
41
When does the vascular shell reabsorb?
Once aqueous humor production begins
42
The hyaloid vasculature reaches peak development in the fetus at ____________ weeks
12 weeks
43
Evidence of the posterior tunica vasulosa lentis can sometimes be seen as a dot-like structure on the posterior capsule of the lens and is called _____________
Mittendorf's dot
44
The degree of resorption of the glial mass and hyaloid vasculature are what define the size of the ___________ at birth
Optic cup
45
Incomplete resorption of the glial mass surrounding the base of the hyaloid vasculature leads to _______________
Bergmeister's Papilla
46
The eye, adnexa and orbit are derived from three major embryonic tissues
Surface ectoderm
Neuroectoderm
Neural Crest Cells
47
Neural crest cells and mesoderm collectively make up the ___________
Mesenchyme
48
Developing vitreous body which consists of a network of fibrils and cytoplasmic processes derived from the developing lens, retina and hyaloid vasculature
Primary vitreous
49
Failure of the posterior tunica vasulosa lentis to resorb and persistence of the primary vitreous results in _______________
Persistent hyperplastic primary vitreous
50
Secondary vitreous consists of mainly what type of collagen
Collagen type II
51
Secondary vitreous forms between the ______ and the ________
Retina and the primary vitreous
52
The primary vitreous is the fully formed eye is known as _____________
Cloquet's canal
53
Cloquet's canal spans from ___________ to the ____________
Retrolental space to the area of martegani
54
The secondary vitreous forms the _________ and __________
Vitreous base and weigert's ligament
55
Tertiary vitreous is secreted by the _______
NPCE
56
The layers of the cornea develop from three sources:
Ectoderm
Mesenchyme
Neural crest cells
57
The corneal epithelium forms from the ____________
surface ectoderm
58
The corneal stroma and bowman's membrane originate from the _____________
Mesenchyme
59
The corneal endothelium forms from ____________ cells
Neural crest cells
60
Descemet's membrane is secreted by the _____________
Corneal endothelium
61
All layers of the cornea are present in the fetus by ______________ months
4 months
62
The sclera forms from condensations of ____________ surrounding the ___________
Mesenchyme surrounding the optic cup
63
After the sclera has completely covered the choroid, small fibers will extend across the posterior scleral foramen and give rise to the ____________
Lamina cribrosa
64
Mesenchyme surrounding the optic vesicle forms the ___________
Choroid
65
Mesenchyme in direct contact with the RPE differentiates into the ___________
Choriocapillaris
66
Endothelial lining of blood vessels formed by the ____________
Mesoderm
67
At the rim of the optic cup, the outer layer differentiates into the
PCE
68
At the rim of the optic cup, the inner layer differentiates into the ______________
NPCE
69
Aqueous humor production and secretion begins at about ___________ months of gestation
4-6 months
70
Stroma elements of the ciliary body originate from _____________
Neural crest cells
71
Musculature of the ciliary body originate from _____________
Mesenchyme
72
Iris posterior pigmented epithelium differentiates from the ________ layer of the optic cup
Inner
73
Anterior myoepithelium differentiates from the __________ layer of the optic cup
Outer
74
What are the only muscles in the body to form from neuroectoderm?
Iris sphincter and Iris dilator muscle
75
Iris stroma and vasculature from from the ________
Mesenchyme
76
Iris vessel endothelium forms from the ________
Mesoderm
77
At the rim of the optic cup, the continuity of the inner and outer layers is observable in the developed eye as the ____________
Pupillary ruff
78
Failure of the optic fissure to entirely fuse can cause a gap in the optic cup called a __________
Coloboma
79
Coloboma of the iris appears as a ___________
Keyhole pupil
80
The pupillary membrane originates from components of the degenerating _________________________
Anterior tunic vasculosa lentis
81
Evidence of resorption of the pupillary membrane can be seen as deficiencies in what layer?
Anterior border layer
82
Often the pupillary membrane does not completely resorb and remnants as a _____________
Persistent pupillary membrane
83
Neural crest cells and Mesenchyme accumulate near the ciliary body and iris root at the ______________________
Iridocorneal angle
84
Slits in the _________ give rise to the anterior and posterior chamber
Mesenchyme
85
The trabecular outflow system is mostly formed by the ______________
Mesenchyme
86
The optic nerve develops from the ____________
optic stalk
87
Invagination of the inferior portion of the optic stalk forms two layers in the stalk:
Outer and inner layers
88
Does myelination of fibers occur beyond the lamina cribrosa?
No
89
The RPE is formed from the __________ layer of the optic cup
Outer
90
What is the first visible layer of pigment in the embryo?
RPE
91
RPE induces formation of the ____________ from the Mesenchyme surrounding the optic vesicle
Choriocapillaris
92
The retina begins to form from the ______________ of the inner layer of the optic cup
Posterior 4/5th
93
The inner layer of the optic cup forms two layers of cells:
Outer proliferative zone
Inner marginal zone
94
The outer proliferative/nuclear zone invades the marginal zone to form the _________ neuroblastic layers
Inner and outer
95
Cells of Inner neuroblastic layer will differentiate into
RGCs
Amacrine cells
Muller cells
96
Cells in the outer neuroblastic layer will differentiate into
Horizontal cells
Bipolar cells
Photoreceptors
97
By what month of fetal development are all layers of the retina present?
8th
98
When do photoreceptors differentiate in development?
Last cells to. And continue to form after birth to increase resolution and sensitivity of the visual system
99
Differentiation of retinal cells follow what pattern?
Central-to-peripheral pattern
100
At 6 months there are so many retinal ganglion cells in the macula that it is the _________ region of the retina for a time.
Thickest
101
At 7 months, the inner retina is displaced forming a depression known as the _________
Fovea
102
Why do cone photoreceptors alter their morphology to become more rod like?
To maximize packing density and increase VA
103
Cone axons in the OPL are oriented in what way?
Elongated and oriented obliquely
104
Temporal retinal blood vessels are last to develop and may not reach maturity until __________ months post-parturition
3 months
105
Pre-mature babies that are exposed to high concentrations of oxygen during neonatal care may develop ___________ if blood vessel development is not complete.
Retinopathy of prematurity which leads to severely impaired vision
106
Eyelids develop as folds of ____________
Surface ectoderm
107
Superior eyelid fold originates from the ____________ process
Frontonasal process
108
The inferior eyelid fold originates from the ______________ process
Maxillary
109
Eyelid structures derived from surface ectoderm
Integument
Conjunctiva
Meibomian glands
Eyelashes
Glands of Zeiss
Glands of Moll
110
Eyelid structures derived from Mesenchyme
Tarsal plates
Superior tarsal muscle
111
Eyelid structures derived from mesoderm
Orbicularis oculi muscle
Levator palpebrae superiors muscle
112
At approximately _________ months gestation, the eyelids separate
7 months
113
Lipid secretions from the ____________ facilitate the breakdown of desmosomes that maintain fusion of the eyelids
Meibomian glands
114
The lacrimal gland arises from epithelial buds in the superotemporal ______________
Forniceal conj
115
Newborn babies do not produce tears until _________ weeks post-parturition
6 weeks
116
The lacrimal sac and nasolacrimal canal originate from the _______________
Surface ectoderm
117
The nasolacrimal system may not completely canalize until after birth in newborns, this may predispose them to infections of the _____________ that can lead to ___________
Lacrimal sac ; dacryocystitis
118
The EOMs are derived from the ______________
Mesenchyme
119
The ____________ muscle is the last to develop and splits off the __________________
Levator palpebrae superioris muscle
Splits off the developing superior rectus muscle
120
Neural crest cells give rise to the ______ and ____________ of the orbit
Fat and connective tissue
121
The _________ is the first orbital bone to form
Maxillary bone
122
All orbital bones are apparent by week ________ of gestation
7
123
The globe reaches its adult size by what age?
3 years
124
The orbit does not reach its adult size until the _________________ years
Middle-teenage
