Embryology of the eye Flashcards
where does the eye develop from?
the neural tube
(= neurectodermal in origin)
what does the notochord induce?
ectodermal layer to thicken and form something called as the neural plate
what then happens to the neural plate?
Neural plate then sinks down and it’s two crests join up together to form the neural tube. And the neural crest cells which are proliferating migrate far and wide to get mixed with this mesoderm here to form the mesenchyme of the head and neck region.
what do optic vesicles grow from?
Optic vesicles grow outwards from diencephalic part of neural tube towards surface ectoderm.
what does the head end of the neural tube form?
the brain
It divides into a number of vesicles which we learn about in neuroanatomy.
Each vesicle is forming a specific part of the brain.
One of these vesicles is called as the diencephalic vesicle and the diencephalic vesicle has outgrowths which grow outwards and laterally,
and they form the optic vesicles just there.
what does the diencephalic vesicle form?
optic vesicles
what happens when optic vesicles reach surface mesoderm?
Optic vesicles reach surface ectoderm🡪 cells of surface ectoderm thicken🡪 lens placode.
what does the lens placode do?
The lens placode starts to push inwards (invaginate), which causes the optic vesicle too, to form an optic cup.
how would you describe the optic cup?
2 layered optic cup is formed.
The lens vesicle ultimately looses its connection with the surface ectoderm.
what happens as the optic cup is forming?
As the optic cup is forming, blood vessels that pass through form a fissure in its inferior wall called as the choroid fissure
what does surface ectoderm form?
forms eyelids, conjunctiva, corneal epithelium
what does the mesenchyme form?
forms, choroid, stroma of cornea, sclera and extraocular muscles.
what do the lens fibres form from?
from epithelium of lens vesicle & later loose their nucleii.
where is mesenchyme derived from?
Mesenchyme derived from mesoderm and neural crest cells
