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37 Cards in this Set

  • Front
  • Back
When does embryological development of the eye start
on ED 22
what are the three germ layers that are responsible for the development of the embryonic plate
1. ectoderm
2. mesoderm
3. endoderm
what will give rise to the CNS
ectoderm-> thickens 3rd week ->neural pate begins to form which gives rise to CNS
when do neural folds fuse
ED 22
the surface ectoderm gives rise to (10)
1. lens
2. corneal epithelium
3.conjunctival epithelium
4.lacrimal glands
5. eyelid epithelium
6. cilia
7. meibomian glands
8, glands of zeis
9.glands of moll
10. epithelium lining of the nasolacrimal system
The neual ectoderm gives rise to (6)
1. retinal pigment epithelium
2. neual retina
3. optic nerve fibers
4. neroglia
5. epithelium of the ciliary body
6.epithelium of the iris( sphincter and dilator muscles as well)
Neural crest gives rise to (7)
1. corneal stroma (Bowmans)
2. corneal epithelium
3. sclera
4. trabecular structures
5. uveal pigment cells
6. uveal connective tissue
7. vascular pericytes
How does the eye look by the end of the embryonic period
the eye is a double layered neural ectoderm derived cup. it contains surface ectoderm derived lens. both are enveloped by a condensed mesochyme comprising a dense outer layer (future cornea and sclera)and an inner vascular layer (ciliary body, iris choroid
what are 4 resulting malformations of the neual tube and optic vesicle
1. anopthalmia
2. nanopthalmia and micropthalmia
3.Synopthalmia
4. congenital cystic eye
What is anopthalmia
optic disk malformation, where the optic disk failures to develop, there is a lack of ocular tissue but EOM's and lacrimal gland are present
What is nanopthalmia/ miropthalmia
malformation of the optic vescicle, where the optical vesicle is formed but no other proper development occured after, this results in a rudimentary or small eye ( which has all recognizable components
what is synopthalmia
fusion of the two eyes, which resulted from malformation of the mesodermal tissue between the optical vesicles
What is cystic eye
disorganized cystic structure caused by errors of the invagination of the retinal disk
what is an example of a optic fissure malformation
coloboma of the iris, ciliary body or retina, this arises from a lack of normal induction, and therefore a lack of uvea tissue formation
what are the optic pits
indentations on either side of the neural tube between ED 22-25
what will the inner layer of the optic cup become
neural retina, inner non-pigmented ciliary body epithelium and the posterior iris epithelium
what is the origin of the optic cup layers
neural ectodermal
what will the outer layer of the optic cup become
RPE, outer pigmented epithelium of the ciliary body and the anterior iris epithelium
what around the optic cup contributes to the connective tissue of the orbit?
Mesochyme
What do neural crest cells form?
corneal stroma and epithelium, uveal stroma and melanocytes, ciliary muscle sclera connective tissue and various mennigeal sheaths
The Mesoderm forms what?
Vascular endothelium and striated muscle
what is induction
during development the formation and growth of structures depends on the tissue differentiation and interaction among local tissues ( prob b/c chemaical rxns)
what structure deveops using induction of the developing optic cup
the lens
Describe the embryological develoment of the lens
surface ectoderm makes contact with the optical vesicle and invagination of the optic cup i initiated on ED 27

at the same time the surface ectoderm adjacent to the vescicle begins to thicken which will form the lens placode

the center of the outer surface of the lens placode invaginates quickly forming the lens pit

invagination continues and the lens vesicle is formed which separates on ED 33

the lens vesicle consists of a hollow sphere, composed of a 1 cell layer surrounded by a thin basal lamina (which eventually becomes te lens capsule)

posterior epithelial cells adjacent to the future vitrous cavity elongates to fill the lumen within the lens vesicle(inducton factor appears to be the developing retina)

posterior epithelial cell become the primary lens fibers and form the embryonic nucleus

cells near the equator of the lens then divide forming the secondary lens fiber cells by the 7th week

the ends of the seconday fibers meet in and upward and inverted y sutures, this regoin continues to develop until birth
when is the lens capsule evident and how does it evolve from
its evident from the 5th week, evolving from the basement membrane of the surface ectoderm and from lens epithelium secreations.
when does he hyaloid occur during embrylogical development
5th week
when is the hyaloid artery fully complete
by the end of the 2nd embryo month
what is the hyaloid artery system
highly branching network fills the vitreous cavity and forms the posterior vascular tunic of the lens
what happens during the 7th embryological week with respect to the hyaloid artery system
branches located near the lens equator join with the annular vesicle which sends loops forward onto the anterior lens surface- forming the anterior vascular tunic of the lens= give nutrients to the developing lens until aqueous humor is produced
when does hyaloid artery reach is peak and what follows its peak
during the third month it peaks and begins to atrophy during the 4th month,when the retina vasoclature is developing
by what month does blood stop flowing though the hyaloid system
7th and its vasoclature should be completely reabsorbed around birth
what is mittendorf's dot
where the hyaloid system attached and didnt fully regress
what is the first area of the retina to develop
RPE retinal pigment epithelium
when does pigmentation occur of the RPF
3-5 weeks
what forms the neural retina
inner layer of the optic cup
which develop first rods or cones
cone
which retinal structure is last to develop
foves