Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Disease, diagnostics and therapeutics > Vision > Flashcards

Vision Flashcards

1
Q

the eye is design to

A

focus light on specialised nerve endings that translate light wave and photons into pictures our brink an understand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

light which reaches photoreceptors of the retina

A

and sends signals via the visual pathways tot he usual cortex in the occipital lobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

human visible light wave lengths

A

400>550nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what makes up the ouster fibrous layer of the eye

A

cornea, conjunctiva and sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

middle vascular layer

A

iris, ciliary body and chorois

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

inner neural layer

A

retain and single layer of retinal pigmented epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the lens

A

focuses light waves onto the retina and specifically the fovea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

iris

A

is a circular structure with a central opening - the pupil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what divides the internal space into an anterior chamber in the front of the iris and a posterior chamber between the iris and the lens

A

iris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

posterior and anterior chambers

A

contain aqueous humour secreted by ciliary body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

vitreous humour

A

fills the main cavity of the eye behind the lens and helps maintain the shape of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

central retinal artery

A

provides nutrients and oxygen for the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

central retinal vein

A

take away oxygen poor blood to be oxygenated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

tetina

A

light sensitive part f the ye containing photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

fovea

A

is the most light sensitive part of the eye- most colour snesiitve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

optic nerve

A

where photoreceptors of the retina send signal via the visual pathways to the visual cortex i the occipital lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

optic nerve is famous as being

A

a blind spot- no photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

the retina contains

A

the neuronal tissue of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

5 types of neurones in the retina

A

rods, cones, amacrine, horizontal, bipolar cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the fovea only contains

A

cones- an area which provides high visual acuity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

rods are

A 
Monochromatic vision
Low intensity light
Single photon
Equally distributed throughout the retina
rhodopsin as visual pigment
22
Q

cones

A 
Colour vision
High light threshold
Higher acuity
Hundreds of photons
Clustered in the macula lutea 
Within the macula lutea is a clustered pit called the fovea, which only contains cones
Highest visual acuity is found here
23
Q

photoreceptors are locate

A

at the back of the retina

24
Q

order of neurones in the retina

A

photoreceptor synapses with bipolar cell with synapses with ganglion cell

25
ganglion cells and bipolar cells are neurones where
signals from rods and cones are integrated
26
rhodopsin
rods
27
iodopsin
cones | - colour blindness results from defects in cone opsins
28
phototransduction occurs via which G protein
Gt
29
what does absorption of light do to colour pigments
isomerise them | -starting a cascade of chemical reactant
30
photo transduction in rods
1) in the dark Sodium (ad calcium) ion influx though cGMP- controlled cation channels which depolarised the rod cells to about -40mV 2) when photon is absorbed by 11-cis retinal it is isomers to all trans retinal (photoisomerisation) 3) rhodopsin is activates and bind to a GTP-bound protein called transducin 4) The GTP-bound alpha submit of transducer dissociates and activates a phosphodiesterase with hydrolyses cGMP- 5'-CMP 5) this closes the cation channels causes hyperpolarisation
31
when photoreceptors aren't stimulated by light
depolarisation | - open cGMP channels
32
when photoreceptors are stimulated by light
hyperpolarisation | -cGMP channels closed
33
Bipolar cells connect photoreceptors to
ganglionic cells
34
ganglionic cells
nerves leave the eye at the optic disk dn become the optic nerve
35
horizontal cells
revive input from multiple photoreceptor cells | - regulated activity of photoreceptor cells and makes adjustments to signals sent to bipolar cells
36
amacrine cells
receive signals form bipolar cells | -regulate and integrate bipolar and ganglionic cells
37
which is the transmitter of the visual pathway
glutamate- the main excitatory nt in the brain
38
phototransduction pathway
1) light travels through layers of transparent neurones- ganglion, amacrine, bipolar and horizontal 2) and is absorbed by the rods and cones a the back of the retina 30 visual information process through several layers of neurones 4) and finally converges on ganglion cells,which send their axons to the brain
39
smaller receptive fields
e. g. 1 ganglion per photoreceptor | - lots of detail
40
large receptive filed
e. g. 3 cones synapse with 1 ganglion - summarises info from 3 cones - less detail
41
when photoreceptors are not stimulated by light
constant state of depolarisation | -constnat release of Glu
42
when the centre of the cone is stimulated by light
the photoreceptor becomes activates | -stimulation result in hyper polarisation due to national channels being close-- > less glutamate produced
43
on centre cells
Glu is inhibitory 1) decrease in Glu release from cone due to hyper polarisation caused by light stimulation 2) due to less Glu inhibition, there is increased depolarisation of the bipolar cells 3) therefore the bipolar cells will release more Glu 4) glu is always excitatory for ganglionic cells 5) therefore INCREASE IN FIRING RATE
44
off centre cells
Glu is excitatory 1) less Glu due to hyper polarisation of cone 2) therefore bipolar cell become hyper polarised 3) decrease in Glu release form bipolar cells 4) decreased firing rate of off-metre ganglionic cells
45
direct pathway in darkness- on centre
Increase in glutamate is inhibitory Therefore increase in MetabotropicGluReceptor Therefore hyperpolarisation Decrease in Glu release Therefore ganglionic cell synapsing with it are less likely to reach threshold Action potential is less likely.
46
direct pathway in darkness - off centre
Excited by Glu Therefore becomes more depolarized Ganglion which synapses with cell is more likely to reach threshold Increase in likelyhood of AP
47
APs are less likely in
positive centre
48
APs are more likely in
negative centre- tells us it is dark
49
Direct pathway light- On-centre
Decrease in glutamate is excitatory Therefore decrease in MetabotropicGluReceptor Therefore more depolarization Increase in Glu release Therefore ganglionic cell synapsing with it are more likely to reach threshold Action potential is more likely.
50
Direct pathway light- Off-centre
Inhibited by decreased Glu Therefore becomes more hyperpolarized and releases less Glu Ganglion which synapses with cell is less likely to reach threshold decrease in likelihood of AP
51
indirect pathway no light
horizontal and amacrine cells release GABA- inhibitory- contributing to telling us it is dark
52
indirect with light
Horizontal and amacrine cells release less GABA

Disease, diagnostics and therapeutics (53 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions