Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

P1 > Ocular Anatomy 5 Cornea > Flashcards

Ocular Anatomy 5 Cornea Flashcards

1
Q

When does corneal development begin

A

33 days of gestation after the lens cup separates from the surface ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is corneal epithelium derived from? Endothelium? Fibroblasts that produce corneal stroma?

A

Epithelium - surface ectoderm
Endothelium and fibroblasts stroma - neural crest cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What determines the final diameter of the cornea

A

The optic cup diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe development of the cornea

A
  1. Production of a bilayered epithelium and basement membrane separate from the bilayer of endothelial cells and associated basement membrane

At 7 weeks, primitive stroma is formed, infiltrated by fibroblasts which produce collage fibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When is descemet’s membrane formed?

A

3 months gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When are corneal nerves formed

A

By 5 month

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When is the corneal fully formed

A

7 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the average dimensions of the cornea?

A

Horizontal diameter 11.7mm
Vertical diameter 10.6mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the radius of curvature of the anterior and posterior surface of the cornea

A

Anterior 7.8mm
Posterior 6.5mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the thickness of the cornea at the limbus and centrally

A

Limbus 1.1mm
Centrally 0.5mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the refractive index of the cornea

A

1.36

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What meridian is the cornea more curved

A

Vertical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the layers of the cornea?

A

Epithelium
Bowman’s membrane
Stroma (substantia propria)
Descemet’s membrane
Endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What epithelium does the cornea have

A

Stratified squamous superficially and columnar in the deeper layers

Centrally five layers of cells, 10 at limbus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Bowman’s layer

A

Acellular layer consisting of interwoven collagen fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is corneal stroma made up of? What proportion of corneal thickness is stroma?

A

Type I Collagen fibres arranged in a regular lattice
90%

17
Q

Where is the stroma stongest?

A

The anterior corneal stroma has greater mechanical strength than the deeper layers of the stroma, because the lamellae anteriorly are thinner and more inter-woven.

18
Q

What is Descemet’s made up of?

A

Collagen fibres arranged in hexagonal pattern
Basement membrane of the cornea

19
Q

What cells form endothelium?

A

Cuboidal cells

20
Q

What layer cells possess microvilli?

A

Surface epithelium and endothelium

21
Q

What links adjacent cells in epi and endothelium

A

Desmosomes
Hemidesmosomes connect cells to their basement membranes

22
Q

How does corneal epithelium regnerate?

A

Occurs at limbus with migration of cells to cover any defect

23
Q

What are the epithelium and endothelium continuous with?

A

Epithelium continuous with the conjunctiva at the limbus
Endothelium continuous with the lining of the trabecular meshwork

24
Q

What is the innervation of the cornea

A

Long ciliary nerves
From ophthalmic division of trigeminal V1

Form annular plexus of myelinated fibres at the corneal limbus with radial branches extending from this plexus into the corneal stroma to form a subepithelial plexus.
Divisions from this plexus pierce Bowman’s layer to form an intraepithelial plexus of unmyelinated nerves.

25
Q

What are the stimuli of corneal epithelium

A

Pain and cold

26
Q

WhWhat is the width of the limbus

A

1.5-2mm
(corneoscleral junction 1mm posterior to the conjunctival libus

27
Q

What is the anatomical libus?

A

Defined by Schwalbe’s line

Posterior to the surgical libus

28
Q

What is the outer surface of the libus marked by?

A

Internal scleral sulcus (groove) contains trabecular meshwork and canal of Schlemm

29
Q

What is Schwalbe’s line

A

Marks the end of Descemet’s membrane and the trabecular meshwork begins just posterior to this

30
Q

What lines the trabecular meshwork

A

Endothelium

31
Q

How does aqueous get from the trabecular meshwork to the canal of Schlemm

A

Pass between the two in giant vacuoles found in the cytoplasm of the endothelial cells

P1 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions