49 Vision I

Question 1

There are ____ layers in the eye

Answer 1

3

Question 2

The outer layer of the eye consists of?

Answer 2

Sclera, cornea

Question 3

The middle layer of the eye consists of?

Answer 3

Choroid, ciliary body, iris

Question 4

The inner layer of the eye consists of ?

Answer 4

Retina, epithelium of the ciliary body, epithelium of the iris

Question 5

The sclera consists of __________ cells.

Answer 5

Collagen fibroblast

Question 6

What is the limbus?

Answer 6

The corneoscleral junction

Question 7

The cornea accounts for ______ of the total refraction of incoming light?

Answer 7

2/3

Question 8

List the 5 layers of the cornea.

Answer 8

1. Epithelium
2. Bowman’s membrane
3. Stroma
4. Descemet’s membrane
5. Endothelium

Question 9

Branches of the ____________ nerve provide sensory information to the cornea. Lesion of it will lead to?

Answer 9

nasociliary nerve (CNV1);
cornea ulcers

Question 10

The cornea is avascular and thus advantageous for?

Answer 10

corneal grafting

Question 11

In which layer is there a basement epithelium that divides and thus continuous turnover?

Answer 11

Epithelium

Question 12

______________ contains numerous nerve fibers which are sensitive to pain, and for corneal reflex.

Answer 12

Epithelium

*multilayered

Question 13

What is the function of the Bowman’s membrane?

Answer 13

For support, protection against infection

Question 14

What is stroma and what happened if it is damaged?

Answer 14

Regular arrangement of multiple fibroblast nuclei layers to produce transparency.
Damage > reduced transparency (opaque lens)

Question 15

Function of the Descement’s membrane?

Answer 15

Support

as the basement membrane of the endothelium

Question 16

Which of the following is true about the endothelium of the cornea?
A. It undergoes turnover
B. Defect (e.g. corneal edema) will cause reduced transparency
C. Regulates the fluid in and out of the cornea by creating a barrier

Answer 16

All except A

therefore will degenerate as person ages

Question 17

How does the lens acquire nutrients when being avascular?

Answer 17

Receive nutrients from the aqueous humour

Question 18

The lens is covered by _______________.

Answer 18

Lens capsule

Question 19

Inherently tends to be spherical but maintains flattened by _____________.

Answer 19

tension in the zonular fibers

Question 20

Which of the following about the lens are correct?
A. Lens epithelial cells appears around the lens
B. The cells transform into lens fibers towards the equator
C. Nucleus of the lens cells will devoid

Answer 20

All except A

lens epithelium only at the anterior side

Question 21

___________ surface or iris is covered by 2 layers of pigmented epithelium continuous with that of the ciliary epithelium.

Answer 21

Posterior

Question 22

At the further end of the iris, there is _______________ muscles innervated by _________.

Answer 22

Sphincter pupillae;

CN3 (EW nucleus)

Question 23

Which muscle is present along the whole length of the iris? What its the innervation?

Answer 23

Dilator pupillae;

superior cervical ganglion (alpha 1 receptor)

Question 24

The iris epithelium consists of _____layer(s) (pigmented).

Answer 24

2 layers

1. anterior layer: give rise to dilator msucles
2. Posterior layer of epithelial cell

Question 25

The iris epithelium is continuous with the ciliary epithelium in which the outer layer is ___________ while the inner layer is ______________.

Answer 25

pigmented; (further from lens) | non-pigemented (closer to lens)

Question 26

__________ is the major origin of aqeuous humour. How many layers of epithelium does it contain?

Answer 26

Ciliary body; | 2

Question 27

State the flow of aqueous humour.

Answer 27

Ciliary epithelium > secreted into posterior chamber > pupil > anterior chamber > Trabecular meshwork > Canal of Schlemm > episcleral veins

Question 28

_________ is the most common form of glaucoma. It is due to?

Answer 28

Open-angle glaucoma; - slow blockade of the Canal of Schlemm, with wide and open iridocorneal angle - decreased outflow of aqueous humour through the tracbecular meshwork cause gradual reduction of peripheral vision.

Question 29

Why can pilocarpine treat open-angle glaucoma?

Answer 29

It contracts the ciliary muscles (it is a muscarinic agonist)

Question 30

What is close-angle glaucoma?

Answer 30

Closed iridocorneal angle, cannot drain into the trabecular meshwork, causing sudden rise in intraocular pressure, and retinal ganglion cell death.

Question 31

What drug can worsen the angle-closure glaucoma?

Answer 31

Atropine, as it causes relaxation of the ciliary muscle.

Question 32

Name all the layers of the retina.

Answer 32

1. Retinal pigmented epithelium Neural retina 2. Outer nuclear layer 3. Outer plexiform layer 4. Inner nuclear layer 5. Inner plexiform layer 6. Ganglion cell layer

Question 33

Which of the following about the retinal pigment epithelium is correct? A. It contains multiple layers B. It does not undergo mitosis C. It is firmly attached to the choroid normally D. It contains melanin

Answer 33

C and D A: single layer B: It has continuous removal of the outer photoreceptor segments (photopigment) > defects lead to slow blindness

Question 34

The outer nuclear layer contains?

Answer 34

Cell bodies of photoreceptors (rods and cones)

Question 35

The inner nuclear layer contains?

Answer 35

1. Bipolar cells 2. Amacrine cells (for contrast enhancement, movement detection, no axons) 3. Horizontal cells 4. Cell bodies of Muller cells

Question 36

Ganglion cell layer contains?

Answer 36

Ganglion cells: sole output of retina to brain

Question 37

Muller cells are distributed in what layers? | Functions?

Answer 37

Spans the whole length, but cell bodies at the inner nuclear layer Function like astrocytes,

Question 38

Is there any oligodendrocytes in the retina?

Answer 38

No! only Muller cells in which their processes are associated with most retinal cells

Question 39

Retinal detachment is the detachment of __________ from ___________.

Answer 39

Neural retina from the retinal pigmented epithelium

Question 40

The fovea is always __________ to the optic disk.

Answer 40

Temporal *avascular!

Question 41

Optic disk only contains _____________, and is pierced by ___________.

Answer 41

axons of ganglion cells; | central retinal artery and vein

Question 42

Meninges of optic nerve continuous with that of brain: hence ________________ of optic nerve is continuous with that of the brain > extends to sclera behind the optic disk. Clinical significance?

Answer 42

subarachnoid space; Raised intracranial pressure transmitted along the SAS to the region behind the optic disc led to papilledema (swelling of optic disk)

Question 43

Other than hydrocephalus, name a cause of papilledema.

Answer 43

glaucoma