Ocular Embryology (Done)

Question 1

Which embryological layer does NOT contribute to ocular structure development?

Answer 1

ENDODERM (forms the gut, most glands and inner lining of digestive & respiratory tubes)

Question 2

What is the Mesoderm used to develop?

Answer 2

Notochord, muscles, and mesenchyme

|&raquo_space;Mesenchymge gives rise to dermis, circulatory system, and Connective tissue.

Question 3

What is the Ectoderm responsible for in development?

Answer 3

Consists of surface and neural ectoderm

|&raquo_space;Overall used for CNS development as well as epidermis and associated skin, hair, nails, etc.

Question 4

On Day 22, two neural folds develop in the ectoderm and fuse together forming the _____________.

Answer 4

Neural tube

Question 5

On day 25, neural ectoderm on each side of the neural tube begins to grow outward, forming ____________.

Answer 5

Optic vesicles.

Question 6

Each optic vesicle invaginates and forms a two-layered optic cup with a _________.

Answer 6

Optic stalk

Question 7

Which structure is the last structure to close during formation of the optic cup?

Answer 7

Embryonic Fetal Fissure

Question 8

The hyaloid plexus within the vitreous cavity eventually disintegrates, but the posterior hyaloid artery persists as the _______________.

Answer 8

Central Retinal Artery

Question 9

What happens if the fetal fissure does not close properly?

Answer 9

Results in a COLOBOMA

Question 10

Which location of coloboma is the most common?

Answer 10

Inferior colobomas due to inferior location of the embryonic fissure.

Question 11

Which 3 structures in the eye does the Inner Layer of the Optic Cup become?

Answer 11

1. Neural retina
2. NPCE
3. Post. pigment layer of the Iris

Question 12

Which retinal cells are found in the Outer Neuroblastic layer (formed from Inner Layer of Optic cup)?

Answer 12

1. Photoreceptors
2. Bipolar cells
3. Horizontal cells

Question 13

Which retinal cells are found in the Inner Neuroblastic layer (formed from Inner Layer of Optic cup)?

Answer 13

1. Amacrine cells
2. Muller cells
3. Ganglion cells

Question 14

Which layer of the retina is the FIRST to develop?

Answer 14

RPE

Question 15

Which area of the retina is the first to begin cell differentiation, but the LAST to complete development?

Answer 15

MACULA

Question 16

In what order do the cells of the neural retina develop?

Answer 16

Ganglion»Horizontal»Cones»Amacrine»Bipolar»Rods»Muller cells

Question 17

At what age is foveal maturation completed?

Answer 17

4 years old

Question 18

What structures are formed from the OUTER layer of the optic cup?

Answer 18

1. RPE
2. Pigmented ciliary body epithelium
3. Anterior Iris epithelium

Question 19

While the optic vesicles begin to form, the adjacent surface ectoderm thickens and forms the ___________.

Answer 19

Lens placode

Question 20

Primary lens fibers from the ______________.

Answer 20

Embryonic nucleus

*Remember, posterior lens epithelium is NOT present in adults.

Question 21

Which lens fibers are responsible for producing the inverted Y sutures seen in the fetal nucleus?

Answer 21

Secondary lens fibers

Question 22

What does Induction mean? and given an example from ocular embryology.

Answer 22

Term referring to how the development of one tissue influences the development of another tissue
»ex. optic cup formation stimulates lens development.

Question 23

What forms the corneal epithelium?

Answer 23

Surface ectoderm

Question 24

Aside from corneal epithelium, what is responsible for producing the remaining layers of the cornea?

Answer 24

Neural crest cells (specialized type of neural ectoderm)

Question 25

Which structures in the eye are produced by Surface ectoderm?

Answer 25

Think “surface” structures
Epithelium, lens, and glands
ex. corneal/conjunctival/eyelid epithelium
»Meibomian, Zeis, Moll, Krause, and Wolfring glands
»Lacrimal gland, lacrimal sac, canaliculi, nasolacrimal duct, and caruncle

Question 26

Which structures are made from Neural Ectoderm?

Answer 26

1. Neural retina, RPE, & neuroglia.
2. Epithelium of CB & Iris
3. Sphincter & Dilator (mesoderm generally develops muscle tissue)
4. Optic nerve fibers

Question 27

Which structures are formed from the Neural crest?

Answer 27

1. Corneal layers except for epithelium (endothelium develops first)
2. Trab. meshwork
3. Iris & CB stroma
4. Sclera & choroid
5. Vitreous

Question 28

Irregular iridocorneal adhesions occur as a result of abnormal neural crest cell development and are characteristics of which type of anomalies?

Answer 28

Axenfeld’s & Reiger’s anomalies

Question 29

Congenital glaucoma is often characterized by _____________, an enlarged eye prior to age 3 secondary to elevated IOP.

Answer 29

Buphthalmos

Question 30

Which structures are made from Mesoderm?

Answer 30

1. EOM’s
2. Endothelium of blood vessels
3. Orbicularis Oculi
4. Levator palpebrae
5. Muscle of Muller