Embryology Development of the Eye Flashcards
When does the eye begin to develop?
Week 4
What are the three embryonic sources of the eye
Neuroectoderm
Surface ectoderm
Mesoderm/Neural crest
What part of the brain does the eye develop from
Prosencephalon
that will divide and the eye forms from the Diencephalon
What are the 5 parts of the optic groove
Optic sulcus Optic vesicle Optic stalk Optic Cup Optic fissure
THe outer and inner layer of the optic cup make up the?
Retina
innerlayer makes up the Neural retina
outerlayer: Pigmented retina
Neuroectoderm
What makes up the Iris and what are their embryological development
Epithelium= Neuroectoderm
Stroma= Mesenchyme
Smooth muscle cells = Neuroectoderm (only muscles that come from neuroectoderm
What makes up the ciliary body and what are their embryological development
Epithelium= Neuroectoderm
Smooth muscle cells = Mesoderm
-ciliary muscle=mesoderm and neural crest
What is found inbetween the Developing pigment epithelium of retina and the Developing neural layer of epithelium
Intraretinal space
this will disappear as the two layers will fuse together during development
if they dont fuse you will get a detached retina
- common in marfans
- downs syndrome
- major head trauma
What embrylogical cells make up the cornea
Surface ectoderm epithelium
Anhiridia
Lack of iris tissue or complete absence of the iris
caused from arrested of development at rim of optic cup during week 8
may be associated with glaucoma, cataracts, and other eye abnormalities
Pax6 gene mutation
How does the lens begin to form
Induced by the optic cup through cell to cell interaction on the lens placode
What is the progression of the lens development
Lens placode- thickening of the Surface ectoderm
to
Lens pit- invagination
to
Lens Vesicle - Migrateds into the optic cup
What is the embroylogical cell of the lens
Anterior lens epithelium
Primary lens fibers
secondary lens fibers
all surface ectoderm
Congenital Cataracts
Lens is opaque and frequently appears grayish white
causes:
genetics
rubella virus of the mother between 4-7 weeks
radiation
Enzyme deficiency
-congenital galactosemia- galactose build up
What are the parts of the sclera and what are their embryological cell
Outerlayer (dura)= mesenchyme
fibrous= Mesenchyme
forms stoma of cornea
What are the parts of the Choroid and what are their embryological cell
Choroid= Neural Crest
Inner layer (pia and arachnoid) = Neural crest
vascular = mesoderm
WHat is the pupillary membrane and what does it do
Will cover the lens during development and then will go away
is a transient structure
part of sclera
What is the Vitreous Humor and what does it develop from
Helps nurish the eye and is made from choroid
Congenital Glaucoma
Whole eye is opaque
Elevated intraocular pressure
results from abnormal development of the drainage mechanism of aqueous humor (scleral venous)
causes: genetics mutations in CYP1B1 (85 percent of time)
rubella infection
What are the Extra ocular muscles and what do they develop from
Prechordal Mesenchyme: SR, IR, LR, MR, SO, IO
What is the blood supply to the embryonic eye
Hyaloid Artery
-branch off of the ophthalimic A
supplies the inner layer of optic cup, lens vesicle, mesenchyme in optic cup
What does the Hyaloid artery turn into
Turns into the central Retinal Artery though will degenerate and only supply the retina
What does the choroid plexus turn into and when does it develop
the choroid vessels develop in the choroid during the 15th week
turn into the anterior and posterior cilary artteries
What happens if the Hyaloid artery persists
Usually is benign but will see a floating artery there and this usually occurs in an individual were the eye is microphthalmic
-small eye
What embryological cell makes up the OPtic nerve and what are the two layers of the neuroblasts
Neuroectoderm
Rods and cones
Ganglion cells
What purpose does the optic stalk serve as
Provides a tract for the optic nerves to grow and obliterate its cavity
the hyaloid artery will also migrate into the stalk via the optic fissure
Papilledema
Increased intracranial pressure slows venous return from retina causing fluid accumulation of the optic disk
can see the optic disc much more prominetly
Coloboma
Iris does not completely form a circle
failure of optic fissure to close leaving a gap
causes: environmental factors
autosomal dominat characteristic
cant constrict that portion of the pupil
Diseases that effect the eye and how: Rubella
cataracts
microphtalmos
glaucoma
pigmented retinopathy
Diseases that effect the eye and how: Toxoplasma gondii
Microphthalmia
Diseases that effect the eye and how: Venezuelan equine encephalitis virus
micropthalmia
Diseases that effect the eye and how: Varicella
cataracts
microphthalmia
optic atrophy
