Visual

Question 1

Where is sensation of vision located?

Answer 1

Occipital lobe

Question 2

Visible wavelengths

Answer 2

400-750nm

Question 3

what is the fibrous capsule composed of

Answer 3

the sclera (whites of eyes) and the cornea

Question 4

what does the cornea do

Answer 4

refract light onto the retina

Question 5

What/where is the aqueous humor and what is the purpose of it

Answer 5

In front of the lens, under the cornea is salty water to maintain interocular eye pressure

Question 6

Constriction of pupil

Answer 6

Improved depth focus

Question 7

Convergence of eyes

Answer 7

Objects remain in focus on corresponding parts of the two retina (go cross eyed)

Question 8

Vitreous humor

Answer 8

jelly like main part of eye, maintains interocular pressure

Question 9

what does the retina do?

Answer 9

Receives light and turns it into neural signals, is an outgrowth of the thalamus

Question 10

Fovea

Answer 10

Has highest resolution of vision and densest number of CONE photoreceptors

Question 11

Optic nerve (cranial nerve II)

Answer 11

where ganglia cells from the retina leave the retina and goes to the brain

Question 12

What is the Choroid and pigment epithelium

Answer 12

Choroid: vascular layer of eye between sclera and retina

Pigment epithelium: deepest layer of retina, black to absorb light so theres no refraction

Question 13

Cataract

Answer 13

Cells die in the lens and becomes opaque

Question 14

Accomodation (in near response)

Answer 14

contraction/relaxation of ciliary muscle and loss of tension on zonular fibres to alter lens shape (more spherical) and change refractive power

Question 15

Constriction of pupil

Answer 15

Improved depth focus

Question 16

How does the neural component of eye work?

Answer 16

converts light energy into patterned changes of membrane potential that the brain can decode to create visual perceptions

Question 17

Rods detect what light (dark or bright)

Answer 17

detect light in low light (not colour sensitive)

Question 18

Cones

Answer 18

detect colours in bright light - have S, M and L receptors (short medium long)

Question 19

Photopigments

- hint (opsin + vit A)

Answer 19

Makes photoreceptors light sensitive made of an opsin and retinal
Rods: Rhodopsin
Cones: Photopsin

Question 20

Rod phototransduction (in the dark)

Answer 20

In absense of light, 11-cis retinal is non-activated, intracellular cGMP levels are high and open cGMP-gated channels allowing influx of Na, depolarising the cell and glutamate is constantly released onto bipolar cells

Question 21

Cone phototransduction

Answer 21

In light, retinal changes to active all-trans isoform which activates transducin which tells cGMP phosphodiesterase to break down cGMP = causing closing of cGMP gated channels and hyperpolarising the cell reducing glutamate release

Question 22

Cone phototransduction (in the dark)

Answer 22

In absense of light, 11-cis retinal is non-activated, intracellular cGMP levels are high and open cGMP-gated channels allowing influx of Na, depolarising the cell and glutamate is constantly released onto bipolar cells

Question 23

Cone phototransduction (in the light)

Answer 23

In light, retinal changes to active all-trans isoform which activates transducin which cGMP phosphodiesterase to break down cGMP = causing closing of cGMP gated channels and hyperpolarising the cell due to K+ leakage, reducing glutamate release. This acts as a signal that light is present.

Question 24

Colour blindness can be i……… or a…………

Answer 24

Inheirited (congenital) or aquired (due to disease and damage to the optic nerve or retina)

Question 25

Colour blindness can be i......... or a............

Answer 25

Inherited (congenital) or acquired (due to disease and damage to the optic nerve or retina)

Question 26

Diseases that damage the optic nerve or retina

Answer 26

Glaucoma: increase in pressure in aqueous humor Diabetes Alzheimer's or Parkinson's

Question 27

``` Visual pathway (5 locations) - R, SC, LGN, SN, Pr ```

Answer 27

Retinal ganglion cell axons leave retina at the optic nerve and send axons to parts of brain to the - Superior colliculus: coordinates rapid movement and tells you to react to visual stimuli Lateral geniculate nucleus of thalamus: decides what information is worthy to be processed and is then send to the occipital lobe Suprachiasmatic nucleus: involved in circadian rhythms Pretectum: coordinates pupillary light reflex

Question 28

``` Visual pathway (5 locations) - R, SC, LGN, SN, Pr ```

Answer 28

``` Retinal ganglion cell axons leave retina at the optic nerve and send axons to parts of brain to the: Superior colliculus Lateral geniculate nucleus of thalamus Suprachiasmatic nucleus Pretectum ```

Question 29

Superior colliculus

Answer 29

coordinates rapid movement and tells you to react to visual stimuli

Question 30

Lateral geniculate nucleus of thalamus

Answer 30

decides what information is worthy to be processed and is then send to the occipital lobe

Question 31

Suprachiasmatic nucleus

Answer 31

Involved in circadian rhythms

Question 32

Pretectum

Answer 32

coordinates pupillary light reflex

Question 33

What is the blind spot

Answer 33

where the axons from the retina leave and head to parts of the brain (optic nerve/optic disc)