Final: Eye Develoment

Question 1

Development of the preplacodal region involves activation of _____ pathway & inhibition of _____ & _____.

Answer 1

FGF.

Wnt & BMP

Question 2

Arrange the following in order of least to highest concentration with increasing BMP concentration.
Neural plate
Placodes
Neural crest

Answer 2

Placodes, Neural crest, Neural plate

Question 3

The optic stalk forms the _____.

Answer 3

Optic vesicle

Question 4

The _____ artery uses the _____ _____ & _____ _____ to pass into the posterior chamber of the eye.

Answer 4

Hyaloid
Choroid fissure
Optic stalk

Question 5

Absence of the Pax6 gene in mammals results in…?

Answer 5

Early optic vesicle formation, but not rest of eye

Question 6

Absence of the Pax6 gene in mammals results in…?

Answer 6

Early optic vesicle formation, but not rest of eye

Question 7

High concentrations of _____ inhibit Pax6 expression.

Answer 7

Shh

Question 8

Shh is in high concentrations in the _____ (distal/proximal) part of the eye and induces expression of Pax2.

Answer 8

Proximal

Question 9

T/F: Lens fiber cells are postmitotic.

Answer 9

True

Question 10

_____ accumulate in the vitreous humor and stimulate formation of lens fibers.

Answer 10

FGF

Question 11

What is the iris derived from?

Answer 11

Pigmented layer of retina

Question 12

What is the term for absence of an eye resulting from a mutation in RAX, attributed to lack of formation of the optic vesicle?

Answer 12

Anophthalmos

Question 13

What is the term for an eyeball that is slightly smaller or almost vestigial (compared to the normal one) and is associated with intrauterine infections & rubella syndrome?

Answer 13

Microphthalmos

Question 14

What is the term for nonclosure of the choroid fissure of the iris during the 6th or 7th week of development?

Answer 14

Coloboma of the Iris