Embryology Development of the Eye

Question 1

When does the eye begin to develop?

Answer 1

Week 4

Question 2

What are the three embryonic sources of the eye

Answer 2

Neuroectoderm
Surface ectoderm
Mesoderm/Neural crest

Question 3

What part of the brain does the eye develop from

Answer 3

Prosencephalon

that will divide and the eye forms from the Diencephalon

Question 4

What are the 5 parts of the optic groove

Answer 4

Optic sulcus
Optic vesicle
Optic stalk
Optic Cup
Optic fissure

Question 5

THe outer and inner layer of the optic cup make up the?

Answer 5

Retina

innerlayer makes up the Neural retina

outerlayer: Pigmented retina

Neuroectoderm

Question 6

What makes up the Iris and what are their embryological development

Answer 6

Epithelium= Neuroectoderm

Stroma= Mesenchyme

Smooth muscle cells = Neuroectoderm (only muscles that come from neuroectoderm

Question 7

What makes up the ciliary body and what are their embryological development

Answer 7

Epithelium= Neuroectoderm

Smooth muscle cells = Mesoderm
-ciliary muscle=mesoderm and neural crest

Question 8

What is found inbetween the Developing pigment epithelium of retina and the Developing neural layer of epithelium

Answer 8

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

Question 9

What embrylogical cells make up the cornea

Answer 9

Surface ectoderm epithelium

Question 10

Anhiridia

Answer 10

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

Question 11

How does the lens begin to form

Answer 11

Induced by the optic cup through cell to cell interaction on the lens placode

Question 12

What is the progression of the lens development

Answer 12

Lens placode- thickening of the Surface ectoderm
to
Lens pit- invagination
to
Lens Vesicle - Migrateds into the optic cup

Question 13

What is the embroylogical cell of the lens

Answer 13

Anterior lens epithelium
Primary lens fibers
secondary lens fibers

all surface ectoderm

Question 14

Congenital Cataracts

Answer 14

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

Question 15

What are the parts of the sclera and what are their embryological cell

Answer 15

Outerlayer (dura)= mesenchyme
fibrous= Mesenchyme
forms stoma of cornea

Question 16

What are the parts of the Choroid and what are their embryological cell

Answer 16

Choroid= Neural Crest

Inner layer (pia and arachnoid) = Neural crest

vascular = mesoderm

Question 17

WHat is the pupillary membrane and what does it do

Answer 17

Will cover the lens during development and then will go away

is a transient structure

part of sclera

Question 18

What is the Vitreous Humor and what does it develop from

Answer 18

Helps nurish the eye and is made from choroid

Question 19

Congenital Glaucoma

Answer 19

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

Question 20

What are the Extra ocular muscles and what do they develop from

Answer 20

Prechordal Mesenchyme: SR, IR, LR, MR, SO, IO

Question 21

What is the blood supply to the embryonic eye

Answer 21

Hyaloid Artery
-branch off of the ophthalimic A
supplies the inner layer of optic cup, lens vesicle, mesenchyme in optic cup

Question 22

What does the Hyaloid artery turn into

Answer 22

Turns into the central Retinal Artery though will degenerate and only supply the retina

Question 23

What does the choroid plexus turn into and when does it develop

Answer 23

the choroid vessels develop in the choroid during the 15th week

turn into the anterior and posterior cilary artteries

Question 24

What happens if the Hyaloid artery persists

Answer 24

Usually is benign but will see a floating artery there and this usually occurs in an individual were the eye is microphthalmic

-small eye

Question 25

What embryological cell makes up the OPtic nerve and what are the two layers of the neuroblasts

Answer 25

Neuroectoderm

Rods and cones
Ganglion cells

Question 26

What purpose does the optic stalk serve as

Answer 26

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

Question 27

Papilledema

Answer 27

Increased intracranial pressure slows venous return from retina causing fluid accumulation of the optic disk

can see the optic disc much more prominetly

Question 28

Coloboma

Answer 28

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

Question 29

Diseases that effect the eye and how: Rubella

Answer 29

cataracts
microphtalmos
glaucoma
pigmented retinopathy

Question 30

Diseases that effect the eye and how: Toxoplasma gondii

Answer 30

Microphthalmia

Question 31

Diseases that effect the eye and how: Venezuelan equine encephalitis virus

Answer 31

micropthalmia

Question 32

Diseases that effect the eye and how: Varicella

Answer 32

cataracts
microphthalmia
optic atrophy