The eye

Question 1

What is the role of the sclera

Answer 1

Protective layer

Question 2

What is the role of the conjunctiva

Answer 2

Produces fluid for protection

Question 3

What is the role of the cornea

Answer 3

Focuses the light that enters the eye to the back of the retina

Question 4

What is the role of the pupil

Answer 4

Contracts / dilates to allow light to enter the eye

Question 5

What is the role of the lens

Answer 5

Focuses light on the retina by changing shape

Question 6

What muscles allow the lens to change shape

Answer 6

Cillary muscles

Question 7

What is the role of the iris

Answer 7

Controls the amount of light that enters by constricting / dilating pupil

Question 8

What is the role of the choroid

Answer 8

Vascular layer supplying blood

Question 9

What is the role of the retina

Answer 9

Photoreceptors that transduce light signals to electrical ones to go to the brain

Question 10

What is the role of the macula

Answer 10

Part of fovea
Contains photoreceptors

Question 11

What part of the eye is responsible for signal transduction

Answer 11

Retina

Question 12

What are the 2 different types of photoreceptors

Answer 12

Rods
Cones

Question 13

Why do cones having a high convergence rate matter

Answer 13

Produces a higher resolution of image

Question 14

Summarise the cells involved in visual transduction

Answer 14

Light hits cones/ rods
Signal passes to bipolar cells
Signal passes to ganglion nerve fibres

Question 15

Summarise the pathophysiology of signal transduction without light

Answer 15

cGMP stimulates Na+ channels
Causes depolarisation of the cell
Increase in Ca2+ ions
Glutamate neurotransmitter released

Question 16

Summarise the pathophysiology of signal transduction with light

Answer 16

Light absorbed
11-cis-retinal changes shape to all-trans-retinal
Opsin undergoes conformationla change
transducin activated
phosphodiesterase activated
decrease in cGMP
decrease in Na+
Hyperpolarisation
decrease in glutamate release

Question 17

Define glaucoma

Answer 17

Damage to optic nerve due to increased IPO

Question 18

Where is the aqueous humor secreted from

Answer 18

Cillary body

Question 19

Where does the aqueous humor drain

Answer 19

Anterior drainage angle

Question 20

What muscle is responsible for pupil dilation

Answer 20

radial

Question 21

What muscle is responsible for pupil constriction

Answer 21

Circular

Question 22

What state is the cillary muscle in for far vision

Answer 22

Relaxed
lens is thin

Question 23

What pulls the lens taut in far vision

Answer 23

Intraocular pressure

Question 24

What state is the cillary muscle in for near vision

Answer 24

Contracted

Question 25

What shape is the lens for near and far vision

Answer 25

Near = curved Far = flat

Question 26

What mediates the control of the collary muscles

Answer 26

Parasympathetic system

Question 27

What photoreceptors allow coloir to be seen

Answer 27

Cones

Question 28

What photoreceptors allow us to see in black and white

Answer 28

Rods

Question 29

Where are cones the most abundant

Answer 29

Fovea

Question 30

Where are rode the most abundant

Answer 30

Periphery