Anatomy

Question 1

What is the corneal epithelium?

How many layers?

What are these layers?

Answer 1

Stratified, squamous, non keratinised and non secretory

5-7 layers

Basal layer of columnar cells (tightly adhered to the basement membrane)
2-3 layers of interdigitating wing cells
3-4 layers of flattened nucleated squamous cells (squames)

Question 2

How are the superficial layers of the epithelium joined?

Wing cells?

Basal cells

Answer 2

Desmosomes- tight junctions

Desmosomes + Gap junctions

Desmosomes + gap junctions + Hemidesmosomes

Question 3

What is the lamina Lucida and the lamina densa?

Answer 3

The basement membrane, between the epithelial cells and stroma

Question 4

What % of the cornea does the stroma make up

Answer 4

90%

Question 5

What produces the lamellar stroma?

What do they produce?

Answer 5

Stromal fibroblasts (keratocytes)

Proteases

Question 6

What is the main collagen type of the cornea?

Answer 6

Type 1

Question 7

Overproduction of what causes corneal melting?

Answer 7

Proteases, inflammatory cells and bacteria

Question 8

What secretes the descemets membrane?

Answer 8

Corneal endothelium

Question 9

How many cell layers is the endothelium?

What shaped cells?

How are endothelial cells connected?

Answer 9

Single cell layer

Low cuboidal

Tight junctions and gap junctions

Question 10

What is the process for stromal hydration?

Answer 10

Na K ATPase

Question 11

What provides corneal epithelial nutrition?

Answer 11

Tear film
Limbal blood vessels
Aqueous humour

Question 12

When does stromal healing occur?

Answer 12

Once re epithelialisation has occurred

Question 13

Is the sphincter muscle in the iris supplied by the sympathetic or parasympathetic NS?

Which nerve?

What does it do to the pupil- constricts/ dilated?

Answer 13

Parasympathetic

Oculomotor nerve III

Constricts the pupil

Question 14

Is the dilator muscle in the iris supplied by the sympathetic or parasympathetic NS?

Answer 14

Sympathetic

Question 15

What is the function of the ciliary body?

Answer 15

Secreting aqueous
Nourishing the lens
Muscle for accommodation of the lens

Question 16

What part of the ciliary body secretes the aqueous humour?

Answer 16

Non pigmented epithelium

Question 17

Where does the lens get its nutrients from?

Answer 17

Aqueous humour

Question 18

Where does conventional drainage occur for aqueous?

Answer 18

Iridocorneal angle

Question 19

What is ‘unconventional drainage’ for aqueous outflow?

Answer 19

Via the uveoscleral outflow

Through the ciliary body and choroid

Question 20

Does IOP increase or decrease with age?

Answer 20

Increase

Question 21

What is the vitreous made up of?

Answer 21

99% water
Collagen
Hyaluronic acid
Few cells (hyalocytes)

Question 22

What are the 10 layers of the retina?

Answer 22

Question 23

What is the retinal pigment epithelium continuous with? LAYER 1

Where are the cells not pigmented?

Answer 23

Outer pigmented epithelium of the ciliary body

Tapetum lucidum

Question 24

What does the visual cell layer have in the retina? LAYER 2

Function of these cells?

Answer 24

PHOTORECEPTORS
Light sensitive cells;
Rods (95%)
Cones (5%) - in the area centralis lateral to the optic disc

Rods - function in dim/ reduced light, detection of shapes/ motion

Cones - function in bright light, sharp visual acuity and colour sensation

Photopigment produce chemical energy when exposed to light, converted in to electrical energy.

Question 25

What is in the outer nuclear layer of the retina? LAYER 4

Answer 25

Photoreceptor cell bodies and nuclei

Question 26

What is in the outer plexiform layer of the retina? LAYER 5

Answer 26

Branching terminals of the rod and come cell axons

Question 27

What is in the inner nuclear layer in the retina? LAYER 6

Answer 27

Cell bodies of the horizontal cells, bipolar cells, amacrine cells and Muller cells

Question 28

What is in the inner plexiform layer in the retina? LAYER 7

Answer 28

Cell processes of inner nuclear layer synapse with ganglion cells

Question 29

What cells are in the nerve fibre layer in the retina? LAYER 9

Answer 29

Ganglion cells (unmyelinated)

Question 30

Which layers do the retinal vessels lie?

Answer 30

Nerve fibre layer 9 Ganglion cell layer 8 Inner plexiform layer 7

Question 31

What is a holangiotic fundus? Species?

Answer 31

Retina is nourished by arteries and veins on its surface Cats and dogs

Question 32

What is an anangiotic fundus? Species?

Answer 32

Vasculature is restricted to the pecten Avian

Question 33

What is a merangiotic fundus? Species?

Answer 33

Horizontal band of vessels (medially a laterally) Rabbit

Question 34

Are photoreceptors in a depolarised state in light or dark?

Answer 34

Dark

Question 35

Are photoreceptors in a hyperpolarised state in light or dark?

Answer 35

Light

Question 36

Which dogs can have an absence of a tapetum?

Answer 36

Merle collies

Question 37

In dogs, long coat length correlates with what type of transition between the tapetum and non tapetum? Gradual or abrupt?

Answer 37

Gradual

Question 38

In dogs, short coat length correlates with what type of transition between the tapetum and non tapetum? Gradual or abrupt?

Answer 38

Abrupt

Question 39

Is the optic disc in the dog myelinated or unmyelinated?

Answer 39

Myelinated

Question 40

Is the optic disc in the cat myelinated or unmyelinated?

Answer 40

Unmyelinated

Question 41

What is a, b and c in an ERG?

Answer 41

A wave photoreceptors B wave layers of the retina C wave RPE

Question 42

Is an ERG a cone or rod dominated response?

Answer 42

Rod

Question 43

Which organ is an essential component of ACAID? (Anterior chamber associated immune deviation)

Answer 43

Spleen

Question 44

What is the only lymphatic drainage of the eye?

Answer 44

Conjunctiva associated lymphoid tissue