Development of the eye Flashcards
The Ectoderm of the eye gives rise to what?
- Lens
- Part of the Cornea
portion of The eyelids
eyelashes and glands in the eyelids
the lacrimal glands
The neuroectoderm forms the
- Retina
- Pigmented epithelium of the Irirs
- Optic Nerve
Mesoderm Forms what in the eye?
Cornia Angioblasts of the Chorioid Layer
Neural crest cells migrate into the mesenchyme from the neural crest and differentiate into
choroid
and
sclera part of the cornea (corneal endothelium)
The chorid is the innder vascularized layer under the scalera
When does eye development begin?
The Start of the 4th week
What is the initial events of formation of the eye
Optic Groove
Optic Vesicle
Optic Stalk
GVS
Anophotalmia
Optic Vesicle does not form correctly.
Lack of eyes
What is the primordia of the lenses?
Lense Placodes Lense Pits Lense Vesicles (PPV)
How are Optic Cups formed
The Optic Vesicle invaginates to form a “CUP”
What are “Linear grooves - retinal fissures”
Form in the Optic Stalk Future site of the Centeral Artery and Vessel of the retina
When is the Optic Stock Lumen obliterated to become the Optic Nerve?
Week 8
What is COLOCBOMA
A defect in the eye Caused by incomplete closure of the Retinal Fissures during week 6 Autosomal Dominate
primary vitreous body Where is it found?
Between the Optic Cup and the Lens Vesicle.
primary vitreous body What does it do?
Lubricates and provides nutrients to the Lens Called Vitreous Humor
What is the pupillary membrane?
Branches of the Hyaloid artery called the Tunica Vasculosa Lentis. The Pupillary Membrane is the most anterior portion of this structure.
The pupil forms before/after the degradation of the pupillary membrane?
After the degradation of the membrane
What is persistent pupillary membrane?
When the pupillary membrane does not completely disintegrate.
What is the cause of congenital cataracts?
The most common causes are
- Trisomy 21
- Maternal Diabetes
- Rubella
- Galactosemia
What are the two layers of the retina?
The thick inner layer - holds the nerves for vision The thin outer layer - pigmentation of the retina.
What are the two layers of the retina separated by?
Intraretinal Space
When does the intraretinal space disappear?
by the 7th week.
(space between the thick and thin membrane)
What is caused by a blow to the eye or head?
Retinal detachment.
What is the light sensitive part of the retina?
The thick inner layer. - becomes the neural retina
What does the neuro retinal contain?
Rods and cones, Cell bodies of neurons
What does the thin-outer wall become?
cuboidal melanin-containing pigmented epithelium.
myelination of the eye nerve takes place when?
After 10-12 weeks of light exposure.
The mesenchyme (nuero crest orgin) surrounding the optic cup differentiates into what?
inner vascular layer- the choroid
outer fibrous layer - the sclera
What is the ciliary body?
Wedged shape extention of the Choroid.
What function does the ciliary body have?
Ciliary Muscle - focusing the lens
Ciliary Process - producing aqueous humor
Dranage of the Aqueous Humor is done by the
trabecular Meshwork - Venus drainage
and
Canal of schlemm-
Congenital Glaucoma
Over production of the aqueous Humor ( Ciliary Process)
Under drainage problem (Trabecular Meshwork or Canal of Schlemm.
Can also be caused by Rubella during pregnancy.
The iris is derived from what structure?
The Optic Cup. Both Layers Thick inner and Thin outer
Connective tissue of the iris is derived from what/
Neurocrest cells
The dilator pupillae is derived from what?
neuroectoderm of the optic cup.
What innervates the dilator Pupillae?
Sympathetic nerves from the Superior cervical Ganglion
What innervates the sphincter pupillae
Parasympathetic nerves from Edinger Weshphal
Eye color is determined by ?
The level of pigment in each layer in the iris Posterior only - blue throughout Iris - brown