Vision

Question 1

3 chambers

Answer 1

anterior, posterior and vitreous chamber

Question 2

Why are the chambers important

Answer 2

Filled with different fluids (ions)
ant = aqueous humor
post =
vit = vitreous humor (sticky gel mass)

Question 3

Lens changes shapes

Answer 3

due to actions of ciliary muscle and zonule fibres

Question 4

Optic disk is

Answer 4

where all the nerves that carry sensory information about the light to optic nerve (cranial nerve 2)

Question 5

Fovea is

Answer 5

the high density of our cone receptors

Question 6

Cone receptors are responsible for

Answer 6

colour vision and high acuity

Question 7

What is normal vision

Answer 7

Emmetropia

Question 8

Features of Myopia include

Answer 8

eyeball being too long, image focused in front of retina not for the distant; corneal surface too curved

Question 9

Hyperopia features include

Answer 9

eyeball too short; refracting system too weak; image not focused on retinal surface

Question 10

Accommodation is where

Answer 10

we look in the distance and then we look at something close up = the change of lens thickness => increase in refractive index
(changes in ciliary muscles and zonule fibres)

Question 11

Increase shape of lens means

Answer 11

accommodation - we can see nearby objects clearer

Question 12

Structures of retina

Answer 12

Outer layer = cone and rod

Question 13

Rod photoreceptors

Answer 13

light intensity

Question 14

Cone photoreceptors

Answer 14

high acuity vision and colour

Question 15

Fovea has a high distribution of

Answer 15

Cones

Question 16

How does Phototransduction work

Answer 16

cGMp levels are high - binds to Na channels - keeping them open - allows Na+ influx - photoreceptor depolarisation - neurotransmitter released from terminal

Question 17

When photoreceptor interacts with light

Answer 17

cGMP levels drop - activation of rhodopsins - cGMP no longer bind Na+ channels - closing them - increased -ve charge causes hyperpolarisation and no neurotransmitter release

Question 18

Rods have single

Answer 18

photopigment

Question 19

Cones contain photopigments that respond to 3 different wavelengths

Answer 19

short, medium, long

Question 20

Dichromacy

Answer 20

colour blindness

Question 21

Protanopia

Answer 21

Blue and green only

Question 22

Deuteranopia

Answer 22

blue and red only

Question 23

Trichromacy is

Answer 23

normal colour vision

Question 24

Why is the Retina important

Answer 24

The retina is a layer of photoreceptors cells and glial cells within the eye that captures incoming photons and transmits them along neuronal pathways as both electrical and chemical signals for the brain to perceive a visual picture.