Eye

Question 1

Corneal stroma/endothelium
Choroid and sclera (w/meso)
iris stroma
connective tissue of extra ocular muscles

ciliary muscle are from…

Answer 1

Neural crest cells of the head mesenchyme

Question 2

Optic nerve, retina, Iris muscles, RPE, vitreous humor

derive from

Answer 2

Neuroectoderm

Question 3

Lens
cornea
conjunctiva/caruncle
eyelid
lacrimal gland and drainage are from..

Answer 3

suface ectoderm

Question 4

Week eye development begins

Answer 4

week 4

Question 5

optic pits

Answer 5

inward bulges of ectoderm on either side of neural tube

Question 6

optic vesicle

Answer 6

increase in cell proliferation leads to large spherical bilge connected to neural tube by a thin optic stalk (all still ectoderm) (~25days)

Question 7

What induces formation of the lens/ derived from?

Answer 7

optic vesicle, made from ectoderm. Lens placode develops here (starts as lens vesicle and then is filled in with cells) (lens=ectoderm)

Question 8

When an eye is formed with no lens, what else may be present?

Answer 8

Microopthalmia or anophthamia

Question 9

Optic cup

Answer 9

Invagination of lens placode, asymmetric with a deep groove on inf. surface (choroid fissure)

Question 10

Artery that runs through the choroid fissure on the inferior aspect of the optic cup

Answer 10

Hyaloid artery (embryonic structure), but will become the central retinal artery

Question 11

What cell types fill up the lens vesicle?

Answer 11

anterior lens cells- cuboidal, single layer
posterior lens cells- multiply and elongate
outermost cells- lens capsule

*newer (secondary) fibers are laid over pre-existing (primary), therefore the oldest cell fibers in center and newest at equator

**first ocular structure to show cellular differentiation

Question 12

35% of the protein in the lens

Answer 12

cristallin

Question 13

Precursors of retina, optic nerve, lens, and cornea are present by what week?

Answer 13

week 6 (develops from inside to out)

Question 14

Incomplete closure of choroidal fissure creates…

Answer 14

Colobomas- incomplete, improperly formed, or depigmented segments in iris, lens, choroid, retina, ciliary body (can be associate w/ microopthalmia)

Question 15

What is the first retina layer to differentiate?

Answer 15

Retinal pigment epithelium. week 3-4

@ week 6- RPE is one cell thick

Question 16

Major events of week 4

Answer 16

Eye development , including RPE

Question 17

Major events of week 5

Answer 17

Lens development begins and Choroid fissure begins to close . corneal differential complete

Question 18

Major events of week 7

Answer 18

Choroid fissure is closed, and 2 layer of optic cup are formed (outer- RPE, NPE of ciliary body, ant. iris/ Inner- neural retina, inner NPE of cb, post. iris)

Question 19

sclera and choroid(w/NC)
vitreous humor 
blood vessels 
extra ocular muscles
pia, arachnoid, and dura of optic nerve

Answer 19

Mesoderm of head mesenchyme

Question 20

Congenital cataracts cause

Answer 20

Rubella, lens is opaque or white

Question 21

Optic stalk

Answer 21

Connects the forebrain and the optic vesicle, will become the optic nerve

Question 22

Week 8

Answer 22

ganglion and amacrine cells

Question 23

Week 12

Answer 23

phtotreceoptors and synapses

Question 24

6 months

Answer 24

cell density in the macula, dural layers around optic nerve (5-7 mo)

Question 25

How do neural crest cells migrate in to form the cornea?

Answer 25

33 days- Between the surface ectoderm and lens vesicle first wave- endothelium Week 8- Between developing end and ectotheilium second wave- stroma and pupillary membrane - splits into ant and post Anterior- stroma and endothelium of cornea Posterior- Stroma of the iris

Question 26

Sclera formation?

Answer 26

Condensation of the mesenchyme around the optic cup, Anterior first (week 5) Muscles attach by week 12

Question 27

Ciliary body formation?

Answer 27

formed by neural crest cells by month 3 | Ciliary epithelium produces zonular fibers

Question 28

What is the Hyaloid system?

Answer 28

the hyaloid artery, mesenchyme derived, degenerates by 3-4 months. This artery produces a network that feeds the developing lens, through the tunica vaculosa lentis.

Question 29

What are the derivatives of the ventral and dorsal ophthalmic arteries in the adult?

Answer 29

ventral o.- medial long posterior ciliary artery | dorsal o. - temporal long posterior ciliary and the short posterior ciliary

Question 30

What are the upper and lower lids developed from?

Answer 30

Upper- frontonasal process | Lower- Maxillary process