Embryology of the Eye Flashcards Preview

Systems: Neurology AB > Embryology of the Eye > Flashcards

Flashcards in Embryology of the Eye Deck (30)
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1
Q

What is the eye an extension of?

A

The brain

2
Q

What does the brain develop from?

A

The neural tube

3
Q

What do the signals sent from the notochord induce?

A

Ectodermal cell thickening

4
Q

How does the neural plate form a tube?

A
  • Development of the neural plate leads to the middle sinking down with a crest either side.
  • The 2 crests come closer together until they meet and form a tube
5
Q

Where is the neural tube situated?

A

Dorsal end of the embryo

6
Q

What is the cranial end of the neural tube divided into?

A

A number of vesicles

7
Q

What does each vesicle form?

A

A different part of the brain

8
Q

Which vesicle do the optic vesicle project laterally from?

A

Diencephalic vesicle

9
Q

How do the optic vesicles grow?

A

Outward and laterally

10
Q

Placode

A

Embryological thickening

11
Q

What happens when the optic vesicles reach the limits of the surface ectoderm?

A

It will send out signals which stimulates the surface epithelium to thicken forming the lens placode

12
Q

How is the optic cup formed?

A
  • The lens placode will start to invaginate (push inwards)
  • The optic vesicle itself will be pushed inwards
  • This leads to the formation of 2 layers known as the optic cup
13
Q

How is the optic cup connected to the neural tube?

A

By a stalk

14
Q

What do the 2 layers of the optic cup form?

A

The layers of the retina

15
Q

Mesenchyme

A

Embryonic tissue

16
Q

How are the choroid and sclera formed?

A

The mesenchyme around the optic cup condenses

17
Q

How is the crystalline lens formed?

A

The lens vesicle which has gone inwards loses its connection to the surface epithelium to form the crystalline lens

18
Q

What does the surface epithelium form?

A

Cornea and the front parts of the sclera

19
Q

How are the eyelids formed?

A

At a later stage some of the tissue folds over to form the eyelids

20
Q

How is the choroid fissure formed?

A

When the lens vesicle is growing and as it is folding inwards there is a blood vessel that grows into it. This creates a little groove in the developing retina and optic nerve creating the choroid fissure.

21
Q

What happens to the choroid fissure?

A

In time the fissure closes off

22
Q

How is the blood supply to the retina formed?

A

The choroid fissure closes off but the blood vessels remain within the substance of the optic nerve and becomes the central retina artery and goes to supply the surface of the retina

23
Q

How many layers does the retina have histologically?

A

10

24
Q

What is the 10th layer of the optic cup formed from?

A

Outer layer of the optic cup

25
Q

What is there between layers 1-9 of the retina and the 10th layer?

A

Potential space

26
Q

How can retinal detachment occur?

A
  • Can occur as a consequence of many diseases
  • In most cases it occurs as a result of fluid entering the potential space separating the inner 9 layers from the outer 10th layer
27
Q

What does the surface ectoderm form?

A
  • Eyelids
  • Conjunctiva
  • Corneal epithelium
28
Q

What does the mesenchyme form?

A
  • Choroid
  • Stroma of the cornea
  • Sclera
  • Extraocular muscles
29
Q

What do the lens fibres form from?

A

Epithelium of lens vesicle and later lose their nuclei

30
Q

What is mesenchyme derived from?

A

Mesoderm and neural crest cells