Development Of The Eye

Question 1

What is the first step of eye development?

Answer 1

The optic vesicle develops and makes contact with the ectoderm

Question 2

What do the optic vesicles develop from?

Answer 2

The optic grooves

Question 3

What do the signals from the optic vesicles bring about?

Answer 3

Thickening of the ectoderm to form the lens placode

Question 4

What happens in week 5 of eye development?

Answer 4

The optic vesicle invaginate along with the placode

Question 5

What has happened at week 5 of eye development?

Answer 5

The optic grooves have formed as outgrowths of the diencephalon and grow into the overlying ectoderm. The optic grooves expand to form the optic vesicles. These vesicles send signals that thicken the ectoderm to form the lens placode. The optic vesicles invaginate with the placode.

Question 6

What has happened by 6.5 weeks of eye development?

Answer 6

The optic cup invagination has given two layers - outer and inner. The lens has fully embedded underneath the ectoderm. The lens is hollow.

Question 7

What does the outer layer of of the optic cup give?

Answer 7

The pigmented layer of the retina

Question 8

What does the inner layer of the optic cup give?

Answer 8

The neural layer of the retina

Question 9

What does the anterior firth of the neural retina become?

Answer 9

The pars ceca retinae

Question 10

What does the pars ceca retinae give?

Answer 10

The ciliary body and iris

Question 11

What cell layer do the ciliary muscles develop from?

Answer 11

Mesoderm

Question 12

Where are the ciliary muscles found?

Answer 12

Overlying the ciliary processes

Question 13

What is the function of the ciliary muscles?

Answer 13

To act on the ciliary processes to impact the shape of the lens. Tighten or loosen suspensory ligaments to allow focus light on the retina.

Question 14

What does the mesenchyme that overlies the iris do?

Answer 14

Form the sphincter pupillae and dilator pupillae to change the chape and size of the iris

Question 15

Where are the light receptors and axons for the optic nerve found?

Answer 15

In the posterior 4/5ths of the pars optica retinae

Question 16

What is the function of the pigmented layer of the retina?

Answer 16

To absorb excess light for focus

Question 17

In what layer of the retina are the cell bodies of the neurons found?

Answer 17

Outer nuclear layer

Question 18

What is found in the inner cell layer of the retina?

Answer 18

Bipolar cells that send signals to the ganglion cell layer

Question 19

How is the optic cup formed?

Answer 19

By invagination of the optic vesicle

Question 20

What is the invagination along the optic stalk?

Answer 20

Choroid fissure

Question 21

How does mesenchyme invade the optic cup and what does it form?

Answer 21

Via choroid fissure. Forms network fibres with vitreous humour between

Question 22

What does the formation of the choroid fissure allow for?

Answer 22

Allows the hyaline artery to access the optic cup. Then extend a branch to the lens vesicle

Question 23

What happens to the artery before birth?

Answer 23

It breaks down and stops supplying the lens and only supplies the neuroretina

Question 24

What does the choroid layer of the eyeball develop from?

Answer 24

The deep layer of undifferentiated mesenchyme

Question 25

What is the sclera?

Answer 25

The outer coating of the eyeball in commutation with the dura matter

Question 26

How is the anterior chambers of the eyeball formed?

Answer 26

Mesenchyme vacuolization

Question 27

Where is the posterior chamber?

Answer 27

Between the iris and suspensory ligaments

Question 28

How does the cornea develop?

Answer 28

The anterior chamber maintains part of its mesenchyme that differentiates and forms the cornea

Question 29

What does the optic stalk become?

Answer 29

The optic nerve

Question 30

How does the optic nerve develop?

Answer 30

The optic stalk grows from the diencephalon. The axons start to grow and push into the lumen so it is lost. The edges of the optic stalk fuse and the hyaloid artery becomes trapped inside. The hyaline artery runs through the centre of the optic nerve with axons surrounding it.