Eye Development Flashcards
Ectoderm gives rise to:
lens and part of the cornea
Neuroectoderm gives rise to:
retina, the pigmented epithelium of the iris, the optic nerve
Neural crest cells give rise to:
choroid, sclera, part of the cornea (corneal endothelium)
Mesoderm gives rise to:
contributes to the cornea and forms the angioblasts of the choroid layer
Location of the optic groove/sulcus
in the future diencephalic region of the prosencephalic neural groove
optic sulcus –> ___ –> ____
optic vesicles, optic stalks
Primordia of the lenses
Lens placodes
How do lens vesicles form?
The lens placodes invaginate into the surface ectoderm, forming lens pits. The edges of the pits approach each other and fuse
Where do retinal fissures develop
develop on the ventral surface of the optic cups and along the optic stalks
Contents of retinal fissures and what they develop
The fissures contain vascular mesenchyme that will form the hyaloid blood vessels: the hyaloid artery and the hyaloid vein.
What do hyaloid vessels become
proximal parts persist as the central artery and vein of the retina
How does the lens receive nutrients
diffusion from the aqueous humor in the anterior chamber of the eye, which bathes its anterior surface, and from the vitreous humor in other parts
Gelatinous matrix secreted by optic disc
Primary vitreous body
Avascular mass of transparent, gel-like, intercellular substance.
Vitreous humor
What is the tunica vasculosa lentis
Branches of the hyaloid artery extend over the lens
Anterior part of the tunica vasculosa lentis
Pupillary membrane
When does the pupil form
after the degeneration of the pupillary membrane
How do the layers of the retina form
The two walls of the optic cup: the thick inner wall and the thin outer wall of the cup. Walls of the cup are continuous with the brain
Cells of thick inner wall differentiate into
Neural retina
Contents of neural retina
Photoreceptors (rods and cones) and the cell bodies of neurons
The thin outer wall becomes the
cuboidal melanin-containing pigmented epithelium.
How does the choroid develop
Differentiation of mesenchyme surrounding the optic cup (largely of neural crest origin) into an inner vascular layer
How does the sclera develop
Differentiation of mesenchyme surrounding the optic cup (largely of neural crest origin) into an outer fibrous layer
What forms the cilliary processes?
The choroid’s medial surface projects toward the lens, formed of capillaries supported by delicate connective tissue
The smooth muscle of the ciliary body
Ciliary muscle
What does the iris develop from
The rim of the optic cup, which grows inward and partially covers the lens
The connective tissue of the iris is derived from
Neural crest cells
The dilator pupillae and sphincter pupillae muscles of the iris are derived from
Neuroectoderm of the optic cup
Cornea forms from three sources:
- The external (anterior) corneal epithelium, derived from surface ectoderm
2, 3. Mesoderm and neural crest cells differentiate into the substantia propria of the cornea and the corneal endothelium.
Eyelids form from:
neural crest cell mesenchyme and from two cutaneous folds of ectoderm that grow over the cornea.
What forms as eyelids open
The bulbar conjunctiva and palpebral conjunctiva
The eyelashes and glands in the eyelids are derived from
Surface ectoderm
How do lacrimal glands form
The lacrimal glands develop from a number of solid buds from the surface ectoderm. The buds branch and become canalized to form the nasolacrimal ducts.
