Neuro - Eye

Question 1

where do most retinal ganglion axon cells terminate

Answer 1

lateral geniculate nucleus

Question 2

where does the lateral geniculate nucleus relay to

Answer 2

visual cortex

Question 3

what are secondary function of retinal ganglionic cells

Answer 3

reflexive eye movement
sleep-wake cycle

Question 4

where do retinal ganglionic axons terminate to control reflexive eye movement

Answer 4

pretectal nucleus

Question 5

where do retinal ganglionic axons terminate to control sleep-wake cycle

Answer 5

suprachiasmatic nucleus

Question 6

what are the three layers in the eye

Answer 6

sclera
choroid
retina

Question 7

what is responsible for the majority of light refraction

Answer 7

cornea

Question 8

what is accommodation

Answer 8

changing your optical power to focus near and far

Question 9

what is myopia

Answer 9

where the light is refracted just short of the retina
short-sightedness

Question 10

what is hyperopia

Answer 10

when the light is refracted refracted to a point behind the retina
long-sightedness

Question 11

which retinal ganglion cells cross into the lateral hemisphere

Answer 11

those coming from the nasal part of the reitna

Question 12

where do retinal ganglion cell axons cross

Answer 12

optic chiasm

Question 13

where contains the highest concentration of photoreceptors

Answer 13

fovea

Question 14

what is the retina formed from

Answer 14

diencephalon (optic vesicle)

Question 15

what are the 5 neuronal types in the eye

Answer 15

photoreceptors
bipolar cells
ganglion cells
amacrine cells
horizontal cells

Question 16

what is located in the outer segment of photoreceptors

Answer 16

discs containing pigment for light detection

Question 17

where are photopigments regenerated

Answer 17

RPE

Question 18

what does light detection at the outer segment lead to and what does this allow for

Answer 18

leads to hyperpolarisation
allows for graded responses

Question 19

where are opsins located

Answer 19

within the membrane of a disc

Question 20

function of opsins

Answer 20

tune sensitivity to particular wavelength

Question 21

what does light induced conformational change of opsins lead to

Answer 21

activation of transducin
activation of cGMP hydrolysis
leads to amplification

Question 22

function of phosphodiesterase in light transduction

Answer 22

converts cGMP into GMP

Question 23

what does low levels of calcium lead to in terms of cGMP

Answer 23

increase in guanylate cyclase activity - increase cGMP

Question 24

what does low levels of calcium lead to in terms of rhodopsin kinase

Answer 24

rhodopsin kinase is activated
phosphorylates rhodopsin
leads to arrestin binding /transducin displacement

Question 25

what are the Na+/Ca2+ ion channels gated by

Answer 25

cGMP

Question 26

features of rods

Answer 26

low spatial resolution
high sensitivity (1 photon)

Question 27

features of cones

Answer 27

high spatial resolution
low sensitivity (>100)
less saturation
rapid recovery
colour vision

Question 28

what does loss of rod and cone function lead to

Answer 28

rod - night blindness
cone - legally blind