Eye Development Flashcards
What are the three embryonic sources for the eye?
Neuroecteoderm, surface ectoderm, mesoderm/NCC
Where does the eye originate from in the brain?
Prosencephalon
What are the parts of the eye in the beginning?
Optic vesicle attached via optic stalk, turns into optic cup (with outer and inner layers) attached by optic stalk, makes a horseshoe shape called optic fissure where hyaloid a/v run
What is the prosencephalon divided into?
Telencephalon (gyri, sulci) and diencephalon (thalamus, hypothalamus, epithalamus, eyes)
What is the retina divided into?
Inner neural retina (rods and cones) and outer pigmented retina
What layer does the retina come from?
Both neural retina and pigmented retina come from neuroectoderm
What layer does the iris come from?
Epithelium and smooth muscle cells come from neuroectoderm, the stroma comes from mesenchyme
What layer does the ciliary body come from?
The epithelium comes from neuroectoderm, the smooth muscles/ciliary muscle comes from mesenchyme
What causes a detached retina?
When the pigmented and neural retinas do not fuse and come together (makes intra-retinal space). Seen in down syndrome or marfan’s syndrome, also in trauma
What is aniridia?
Lack of iris tissue/complete absence of iris due to arrest of development at the rim of the optic cup during week 8, caused by Pax6 gene mutation
What layer does the lens come from?
Surface ectoderm
How does the lens develop
Thickening of surface ectoderm = lens placode which is induced by the optic cup. Placode invaginates to form lens pit which rounds up and forms a lens vesicle that migrates down to space around optic cup
What layer does the epithelium of the cornea develop from? What about the stroma of the cornea?
Epithelium comes from surface ectoderm, stroma (deeper layer) comes from mesenchyme
What is congenital cataracts?
Opaque lens caused by genetics, rubella virus during pregnancy, radiation during pregnancy, enzyme deficiency (congenital galactosemia)
What layer does the sclera come from?
Mesenchyme (is continuous with dura of brain), forms stroma of cornea