Eye

Question 1

What are three layers of eye?

Answer 1

Outer
Middle
Inner

Question 2

What structures present in outer layer eye?

Answer 2

Cornea
Sclera

Question 3

Function of cornea?

Answer 3

Transmission light

Question 4

Function sclera?

Answer 4

White capsule
Tough outer layer- protection

Question 5

What structures are present in middle layer (uvea)?

Answer 5

Iris
Ciliary body
Choroid

Question 6

Function iris?

Answer 6

Contain and control pupil size
Give colour

Question 7

What makes pupil smaller?
Para or symp?
Location?

Answer 7

Sphincter muscles- smaller
Parasympathetic
Iris

Question 8

What makes pupil bigger?
Para or symp?
Location?

Answer 8

Dilator muscles- bigger
Sympathetic
Iris

Question 9

What does ciliary body contain?
Muscle?
Innervation?

Answer 9

Glandular epithelium- produces aqueous humour
Smooth muscle- controls accommodation
Innervated by PNS

Question 10

What does glandular epithelium produce?
Function?

Answer 10

Aq humour
Water electrolyes
Maintains intraocular pressure: 15mmHg

Question 11

Where is pars plana located?

Answer 11

Near iris-sclera junction

Question 12

Function choroid?

Answer 12

At heat sink
Darkly pigmented
Absorb photons

Question 13

Answer 13

Question 14

Structures in inner eye?

Answer 14

Retina
Tear film
Humours

Question 15

Function retina?

Answer 15

Produce vitreous humour- maintain intraocular pressure
Contain rods cones
Convert light to electrical impulses

Question 16

Function fovea centralis?

Answer 16

Where image projected

Question 17

Function macula lutea?

Answer 17

High conc cones

Question 18

What does retinal pigment epithelium contain?

Answer 18

Photoreceptors (rods and cones)

Question 19

Function rods?

Answer 19

Dim lighting, peripheral vision

Question 20

Function cones?

Answer 20

Colour vision

Question 21

3 layers of tear film and function?

Answer 21

1) Anterior lipid (oils)
Secreted meibomium glands
Provide hydrophobic barrier- prevent aqueous layer evaporating
2) Middle aqueous (water, electrolytes and proteins)
Secreted by lacrimal glands
Regulates transport through cornea and prevents infection
3) Posterior mucous
Secreted by goblet cells
Provides hydrophilic layer
Allows for even distribution of tear film

Question 22

What is anterior lipids secreted by?
Function anterior lipids?

Answer 22

Meibomium glands
Provides hydrophobic barrier- prevent aqueous layer evaporating

Question 23

What is secreted by lacrimal glands?
Function?

Answer 23

Middle aqueous
Regulate transport through cornea and prevent infection

Question 24

What is secreted by goblet cells?
Function?

Answer 24

Posterior mucus
Allow even dist film

Question 25

What are 2 humours in eye?

Answer 25

Aqueous
Viteous

Question 26

Function aqueous humour?
Where made?

Answer 26

Produced by ciliary epithelium in ciliary body
Maintains intraocular pressure between 12-20 mmHg

Question 27

What value is intraocular pressure in eye?

Answer 27

12-20 mmHg

Question 28

What is vitreous humour?

Answer 28

Collagen matrix

Question 29

What is night blindness caused by?

Answer 29

Damage to retina

Question 30

Outline photon pathway?

Answer 30

1) Tear film- transmission
2) Cornea- transmission and refraction
3) Aqueous humour- transmission
4) Lens- transmission and refraction
5) Vitreous humour- transmission
6) Ganglion cell- transmission
7) Amacrine cell- transmission
8) Bipolar cell- transmission
9) Horiontal cell- transmission
10) Cone- transduction
11) Rods- transduction
12) Pigmented epithelium- absorb excess photons

Question 31

What structure absorbs excess photons?

Answer 31

Pigmented epithelium

Question 32

What is blood supply eye?

Answer 32

ICA- opthamic artery
ECA- facial artery- eyelid and orbit