the visual system

Question 1

partial decussation

Answer 1

crossing of fibres from temporal visual fields at optic chiasm

Question 2

termination of many are at

and others at

Answer 2

lateral geniculate nucleus

pretectal nucleus

Question 3

3 layers of the eye

Answer 3

retina (inner)
choroid (mid)
sclera (outter)

Question 4

vitreous humour

what does it contain

Answer 4

filling the eye

contains phagolytic enzymes

Question 5

cornea what does it provide

Answer 5

most of refraction

Question 6

how does the lens connect to the eye

Answer 6

ciliary muscles

Question 7

refractive errors

Answer 7

myopia

hyperopia

Question 8

myopia is

Answer 8

to high refractive power

cornea is too rounded or eyeball is too long

Question 9

hyperopia is

Answer 9

eye ball to short

Question 10

the retina has 5 neuronal types which are

Answer 10

photoreceptors
ganglion cells 
bipolar cells
amacrine cells
horizontal cells

Question 11

photoreceptors

photoreceptors is adjacent to

Answer 11

retinal pigment epithelium

Question 12

photoreceptors

outer segment

Answer 12

discs containing pigments for light detection

leading to hyperpolarisation

Question 13

then there is light is there more or less glutamate released from these neurons

Answer 13

less

Question 14

in the dark what happens to neuron

Answer 14

cGMP binds allowing Ca2+ and Na+ into the cell while k+ leaks out

Question 15

in the light the neuron

Answer 15

has no influx of Na+ Ca2+ because cGMP not produced and thus hyperpolarisation

Question 16

opsins what does it bind to

Answer 16

binds to chromophores to be able to detect light

Question 17

opsins are

Answer 17

tune sensitive to particular wavelengths

Question 18

what happens once light is absorbed

Answer 18

conformational change
activation of transducin
activation of cGMP hydrolysis

Question 19

when rhodopsin is phosphorylated

Answer 19

transducin in inactivated

so cGMP cant form and bind

Question 20

what happens to rhodopsin if Ca2+ levels drop

Answer 20

feedback loop forms
stops rhodopsin kinase
so rhodopsin is activated

Question 21

scotopic is

Answer 21

rods threshold to cone threshold

Question 22

mesopic is

Answer 22

cone threshold to rod saturation

Question 23

photopic is

Answer 23

good colour vision

Question 24

colour vision

trichromatic where is blue green and red found

Answer 24

chromosome 7
x chromo
x chromo