13. Eye Development (Dennis) Flashcards
What gives rise to the dilator pupillae and sphincter pupillae Ms.?
The neuroectoderm of the optic cup, coming from the anterior epithelial cells of the iris.
(Smooth muscle.)
These are the ONLY two muscles to arise from neuroectoderm as well.
What artery does the hyaloid artery come off of?
What is supplied by the hyaloid artery?
Hyaloid artery comes off of the opthalmic artery (branch of the internal carotid).
It supplies the inner layer of the optic cup, the lens vesicle, and the mesenchyme of the cavity of the optic cup.
What do the hyaloid vessels give rise to in the adult?
The central A. and V. of the retina.
What causes retinal detachment?
The inner and outer layers of the retinal cup fail to fuse, causing the neuroretina to become detached more easily from the pigmented layer - which is attached to the choroid.
(Occurs more in pts with Marfan’s or Downs. Occurs in trauma.)
What is the choroid derived from?
Neural crest cell derived mesenchyme.
Describe development of the lens.
The lens vesicle has an anterior and a posterior part.
The anterior part forms the lens epihelium .
The posterior wall cells elongate and form the primary lens fibers, eliminating the space between the anterior and posterior walls.
The primary lens fibers elongate, lose their nuclei, and move to the edges of the lens, becoming secondary lens fibers.
(Secondary lens fibers continue to form, but primary lens fibers must last a lifetime.)
What three things is the cornea made of?
Surface ectoderm.
Mesenchyme from the mesoderm continuous with the sclera.
Neural crest cells from the optic cup and corneal epithelium.
What major signaling factor is involved in eye development?
PAX6
What structures of the eye are derived from surface ectoderm?
Lens of the eye and corneal epithelium.
What do the hyaloid blood vessels differentiate from?
The mesenchyme that came in through the slit in the bottom of the optic stalk differentiates into the hyaloid blood vessles
What is the substantia propria?
The transparent CT of the cornea and mesothelium of the anterior chamber.
Aka the stroma of the cornea.
Describe the formation of the lens placode.
The optic vesicle, after pinching off from the forebrain, travels towards the surface ectoderm on the lateral side of the embryo’s developing head. When the optic vesicle arrives, it forms the optic cup. This optic cup induces differentiation of the obtic placode from the surface ectoder.
What comes from the inner and outer layers of the optic cup respectively?
Inner layer (near to the lens vesicle) becomes the neuroretina.
Outer layer becomes the pigmented layer of the retina.
What will the optic stalk differentiate into?
The axons of the optic nerve.
What structures of the eye are derived from neural crest cells?
Choroid
Sclera
Corneal endothelium
Stroma of the iris
