Eye Flashcards Preview

Histology > Eye > Flashcards

Flashcards in Eye Deck (51):
1

What are the three layers of the eye

Corneoscleral coat, uveal tract and retina

2

What is the cornea

A transparent anterior extension of the sclera

3

What does the uveal tract consist of

Anteriorly - iris and ciliary body
Posteriorly - vascularised choroid coat

4

What does the retina consist of

Layers of nerve cells, their processes, support cells and on the outside, a layer of pigmented epithelium

5

What allows the lens to change shape

Its elasticity

6

What does the change in shape of the lens allow

Accommodation for near vision

7

What is in front of the lens

Anterior and posterior chambers

8

What fills the anterior and posterior chambers

Aqueous humor

9

What lies posterior to the lens

The vitreal cavity

10

What fills the vitreal cavity

Vitrius humor

11

Structure of vitrous cavity

Avascular and gelatinous due to collagen fibres and hyaluronic acid

12

What is the conjuctiva

A thin, transparent mucous membrane

13

What lines the conjunctiva

Stratified columnar epithelium with goblet cells, and has a lamina propria of loose connective tissue

14

Where does the conjunctiva run from/to

The corneosclearal margin and reflects over the inner surface of the eyelids

15

Composition of the cornea

Outer layer of thin non-keratinised stratified squamous epithelium sitting on a thin layer of collagen (Bowman's membrane) composed of randomly orientated, condensed thin collagen fibrils

16

What is the stroma

Many layers of precisely orientated hydrated collagen

17

What is between the layers of the cornea

Corneal fibroblasts

18

What is on the inside of the cornea

Layer of endothelium sitting on a layer of meshwork collagen called Duscemet's membrane

19

What causes a Kaiser-Fleischer ring

An accumulation of copper in Duscemet's membrane

20

What is the sclera

A tough coat of collagen and elastic fibres defining the globe

21

What attaches to the sclera

The tendons of the extraocular muscles

22

What does the ciliary body contain

Smooth muscle

23

What is the function of the smooth muscle in the ciliary body

It releases tension on the zonular fibres, during near vision, allowing the lens to round-up

24

How is excess fluid drained from the anterior chamber

Via the canal of Schlemm

25

What causes glaucoma

Drainage of the anterior chamber of the eye is not adequate

26

What is the iris composed of

Loose connective tissue with a layer of pigmented epithelium on its posterior surface

27

What cell is found within the iris

Melanocytes

28

What is the function of the smooth muscle within the iris

Changes the iris diameter

29

Where are the sphincter pupillae muscles found

Near the tip of the iris

30

Function of sphincter pupillae muscles

Under parasympathetic innervation - constrict the pupil

31

Function of dilator pupillae muscles

Under sympathetic innervation - open the pupil

32

What does the ciliary body attach to and how

To the lens by a series of zonular fibres

33

How does aqueous humor flow

From the anterior chamber to the posterior chamber

34

What is the lens

A transparent, biconvex structure made up of lens fibres

35

What are contained within the lens fibres

Proteins called crystalins

36

What covers the lens anteriorly

Outer connective tissue capsule and a layer of simple cuboidal epithelium

37

What is the retina

A complex, thin layer of nervous tissue lining the inner eye

38

What structures are within the retina

Rods and cones

39

What do rods conatin

Rhodopsin - a light sensitive pigment

40

What is contained within cones

One of three epsin pigments - sensitive to either red, green or blue light

41

What structure predominates away from the fovea

Rods

42

What lies at the centre of the retina

The fovea

43

What is at the centre of the fovea

The foveola

44

What happens to the retina at the foveola

It thins and becomes avascular

45

What structure is found at the foveola

Cones

46

What covers the cones at the foveola

The outer plexiform layer

47

What is the optic disc

The site where the axons of the retinal ganglion cells exit the eye to form the optic nerve

48

What must the nerves pass through to create the optic nerve

The sclera

49

What does the optic disc lack

Photoreceptors

50

What are the openings in the sclera that the axons pass through known as

Lamina cribrosa

51

What is the optic disc also known as

The blind spot