The Eye

Question 1

what are the 4 things that the eyes are derived fom

Answer 1

• neuroectoderm
• surface ectoderm
• mesoderm
• nerual crest cells

Question 2

what does the retina, iris, and optic nerve ceom from

Answer 2

neuroectoderm

Question 3

what does the lens of the eye and the corneal epithelium come from

Answer 3

surface ectoderm

Question 4

what does the fibrous and vascular coats of the eye come from

Answer 4

mesoderm

Question 5

what does the choroid, sclera, and corneal epithelium come from

Answer 5

nerual crest cells

Question 6

when does the eye appear

Answer 6

day 22

Question 7

optic vessels ( eye grooves from day 22) later come in contact with surface ectoderm and induce changes and finally form what?

Answer 7

lens placode

Question 8

what does the optic vesicle become when it invaginate and forms the double wall

Answer 8

optic cup

Question 9

what connects the forebrain to the optic vesicles

Answer 9

optic stalk

Question 10

what is inside the renal fissure that develop on the ventral surface of the optic stalk

Answer 10

hyaloid vessels

Question 11

what does the retina develop from

Answer 11

the walls of the optic cups ( outgrowth of forebrain)

Question 12

what becomes the pigmented layer of the retina

Answer 12

the outer thin layer of the optic cup

Question 13

what becomes the neural layer of the retina

Answer 13

the inner thicker layer of the optic cup

Question 14

the posterior part of the retina differentiates into what

Answer 14

rods and cones

Question 15

adjacent ot the rods and cons is the mantle layer which is photoreceptive layer what does it give rise too

Answer 15

• outer nuclear layer
• inner nuclear layer
• ganglion cell layer

Question 16

what is in the optic stalk

Answer 16

• optic nerve
• optic chiasm
• optic tract

Question 17

what is the optic nerve a tract of

Answer 17

diencephalon

Question 18

when is the optic nerve myleniated

Answer 18

3 months of birth ( by oligodendroctyes)

Question 19

what is not capable of regeneration after transection

Answer 19

optic nerve

Question 20

what is completed after 10 weeks of light exposure

Answer 20

the optic nerve fibers

Question 21

what does the most common eye anomalies result form

Answer 21

the abnormal closure of the retinal fissure

Question 22

what is characterized by a local gap in the retina and is usually inferior to the optic disc, in most cases it is bilateral ( due to the defective closure of the retinal fissure)

Answer 22

Coloboma of the Retina

Question 23

what is it called when there is a defect in the iris or the notch in the pupillary margin. this can involve only the iris or extend deeper into the cilliary body and retina

Answer 23

coloboma of the iris

Question 24

what results from the failure of the retina to close during week 6 of development

Answer 24

coloboma of the iris

Question 25

what kind of nose is usually present in children with cyclopia

Answer 25

proboscis ( tubular in the middle of the forehead)

Question 26

what does cyclopia result from

Answer 26

severe suppression of the midline cerebral structures

Question 27

what does holoprosencephaly refer too

Answer 27

when the midline of cerebral stuctures fuse (cyclops)

Question 28

what is it when there is a very small eye or it can be a normal appearing rudimentary eye , the affected side of the face will be undeveloped and the orbit is small.

Answer 28

microphtalmia

Question 29

what is severe micropthalmia a result from

Answer 29

arrested development of the eye before the optic vesicle has formed in weel 4

Question 30

most cases of simple microphtalmia are caused by what

Answer 30

infectious agents like - rubella - toxoplasma ghondii - herpes

Question 31

what is it called when there is a congenital absence of the eye

Answer 31

anophtalmia

Question 32

in anophtalmia what still forms even though the eyelids dont form

Answer 32

eyelids

Question 33

what is it called when early in the 4th week there is a failure in the eye vesicle to form

Answer 33

primary anophtalmos

Question 34

what is it when there is the development of the forebrain that is suppressed and therefore there is an absence of the eye or eyes

Answer 34

secondary anophtalmos

Question 35

what is the extension of the choroid and its medial surface projects towards the lens forming ciliary processes

Answer 35

ciliary body

Question 36

what does the ciliary muscle do

Answer 36

focusing the lens

Question 37

what does the epithelium of the ciliary body develop from

Answer 37

anterior portions of both the outer pigment layer and the inner neural layer of optic cup

Question 38

what do the ciliary processes produce

Answer 38

aqueous humor

Question 39

what circulates through the posterior and anterior chambers and drains into the venous circulaiton via the canal of Schlemm

Answer 39

aqueous humor

Question 40

what are the fibers that come from the ciliary processes

Answer 40

suspensory fibers ( ciliary zonule)

Question 41

what do the suspensory fibers attach to

Answer 41

the lens and they suspend it

Question 42

the inner vascular layer is what

Answer 42

choroid

Question 43

what is the outer fibrous layer

Answer 43

sclera

Question 44

the epithelium of the iris is continuous with what

Answer 44

the epith. of the ciliary body and with the reinal pigment epithelium and nerual retina

Question 45

stroms of iris comes from?

Answer 45

nerual crest cells

Question 46

where are the dilator pupillae and the sphincter pupillae muscles from

Answer 46

the neuroectoderm of the optic cup

Question 47

when does the newborn start to get clor of eyelid

Answer 47

6-10 months

Question 48

chromatophores in the loose vascular CT determine what

Answer 48

eye color

Question 49

if the melanin pigment is in the posterior part of the iris then the color is

Answer 49

blue

Question 50

if the melanin pigment is in the stroma then the wyw will be

Answer 50

brown

Question 51

what is it called when there is almost complete absence of the iris and it happens because of the failure in the development at the rim of the optic cup at week 8

Answer 51

congenital aniridia

Question 52

what is associated with congenital aniridia

Answer 52

glaucoma

Question 53

what gene mutation leads to congenital aniridia

Answer 53

Pax6

Question 54

what does the lens develop from

Answer 54

the lens vesicle ( derivative of surface ectoderm)

Question 55

the anterior wall of the lens is what

Answer 55

lens epithelium

Question 56

at what week do the primary lens fibers reach the anterior walls of the vesicle

Answer 56

week 7

Question 57

what supplies the developing lens

Answer 57

by the distal part of the hyaloid artery

Question 58

the lens depends on diffusion from what

Answer 58

aqueous humore ( anterior chamber of the eye) and the Vitreous humor

Question 59

the hyaloid canal is in the vitreous body which is usually what in human life

Answer 59

usually invisible

Question 60

what is the transparent gel-like substance that is in the vitreous body

Answer 60

vitreous humnor

Question 61

what is the primary vitreous humor derived from

Answer 61

mesnchymal cells of the neural crest origin

Question 62

what is it called when there is a pupillary membrane that is left over covering anterior surface of the lens during the embryonic period is still present

Answer 62

persistent pupillary membrane (doesn't interfere with vision, tends to atrophy)

Question 63

when there is a wormlike structure that is free moving it is a what

Answer 63

persistent hyaloid artery

Question 64

in most cases with persistent hyaloid artery what is the eye

Answer 64

microphtalmic

Question 65

what is the part of the surface ectoderm that turns into transparent, multilayerd, avascular

Answer 65

cornea

Question 66

what 3 things make the cornea

Answer 66

- surface ectoderm - mesenchyme - neural crest cells

Question 67

anteroir chamber of the eye is associated with what

Answer 67

lens and cornea

Question 68

posterior chamber of the eye is associated with what

Answer 68

iris and lens

Question 69

how do the anterior and posterior parts of the eye communicate

Answer 69

through the scleral venous sinus

Question 70

what is the congenital disorder that results form abnormal development of the drainage of the aqueous humor during fetal life

Answer 70

congenital glaucoma

Question 71

congenital glaucoma may result form what

Answer 71

rubella

Question 72

wat is it called wen the lens is opaque and appears graysih white and u can go blind without treatment

Answer 72

congenital cateracts

Question 73

when do the eyelids develop

Answer 73

week 6

Question 74

the eyelids develop from what

Answer 74

neural crest cell mesenchyme and from ectoderm that grows over the cornea

Question 75

at week 10 what happens to the eyelids

Answer 75

they adhere together and they do not open until week 28

Question 76

what are the eyelids called when they are closed

Answer 76

conjuctival sac

Question 77

bulbar conjunctiva covers what

Answer 77

anterior part of the sclera

Question 78

the palperbral conjunctiva lines what

Answer 78

the surface of the eyelid

Question 79

if there is prenatal injury to the CN 3 what can happen

Answer 79

ptosis of the eyelids

Question 80

what is a palparable coloboma ( very rar)

Answer 80

when there is a small notch in the superior eyelid or it can be the whole lid!

Question 81

Cryptophtalmos ?

Answer 81

congenital absence of the eyelids and skin covers them

Question 82

when there is an absence of the palpebral fissure then what

Answer 82

there is cyptophtalmos

Question 83

when there is an oxygen induced retinopathy see in premies it is called

Answer 83

retrolental fibroplasia

Question 84

what is the hereditary degeneratoin and atrophy of the retina , there was degeneration of rods and night time blindness and gun barrel vision

Answer 84

retinitis pigmentosa

Question 85

Retinitis Pigmentosa can be due to what

Answer 85

Bassen-Kornzweig Syndrome ( which can be stopped by a massive doses of vitamin A)