Eye Development Flashcards
What are the three embryonic sources of the eye?
Neuroectoderm
Surface ectoderm
Mesoderm/Neural crest (Mesenchyme)
What is the true origin of the eye?
Prosencephalon (forebrain)
What is the critical period for the eye?
Weeks 4-8
But defects can occur out to birth
What is the prosencephalon?
What can it divide into?
Which one does the eye come from?
Forebrain
Divides into telencephon and diencephalon
Eye comes from diencephalon
What is the optic sulcus?
Invagination of the eye that starts to come out from the brain
What is the optic vesicle?
It’s embryonic source of tissue?
Neuroectoderm
Grows out of optic sulcus and forms optic cup
What is the optic stalk?
Connects the optic cup to the brain
What is the optic fissure?
What runs in this space?
Groove extending along the length of the optic stalk
Vasculature run in this space - Hyaloid a. And v.
What does Coloboma result from?
Failure of the optic fissure to close
How does the optic cup develop?
Begins at week 4
Brain to optic sulcus, optic cup starts to grow out of it and is still connected to the Brian via the optic stalk
How many layers does the optic cup have?
What grows in between the layers?
Outer and inner layer
The space between the layers gives rise to the retina
How does the optic fissure form?
As the cup invaginates, the optic fissure forms
What is the embryological origin of the retina?
Neuroectoderm
What is the embryological origin of the iris?
Neuroectoderm
What is the embryological origin of the ciliary body?
Neuroectoderm
What are the layers of the retina? What is the retina technically?
Inner neural retina
Outer pigmented retina
Technically an extension of the brain
What will surround the retina?
Because it is an extension of the brain, the retina will have meningeal layers
What are the layers of the iris?
Epithelium
Stroma
SMC
What is the embryological origin of the iris epithelium?
Neuroepithelium
What is the embryological origin of the iris stroma?
Mesenchyme
What is the embryological origin of the SMC of the Iris? (Sphincter and dilator ms.)
Neural crest cell
***ONLY Ms. IN BODY COMING FROM NCC
What is the embryological origin of the epithelium of the ciliary body?
Neuroectoderm
What is the embryological origin of the ciliary body’s SMC?
Mesoderm (and NCC)
What is the embryological origin of the lens?
surface ectoderm
how are the lens induced?
When the optic cup touches the surface ectoderm it induces the lens placode to form
Cell-cell interaction
What is the embryological origin of the epithelium of the cornea?
Surface ectoderm
How does the lens placode develop?
As the optic cup and layers grow out, they are going to touch our surface ectoderm and when they do that, induction occurs and the lens placode forms
How does the lens vesicles form?
The lens placode invaginates and forms lens pit
Lens pit rounds up and forms lens vesicle which will migrate down into the space around the optic cup
What is the origin of the corneal stroma?
Mesenchyme