20 Vision

Question 1

Locate the pupil on the eye and explain its purpose…

Answer 1

The opening that allows light to enter the eye and reach the retina

Question 2

Locate the Iris and expalins its purpose

Answer 2

circular muscle that controls the size of the purple

Question 3

Locate the Cornea and explain its purpose

Answer 3

The transparent surface that covers the pupil and iris

Question 4

what is the sclera? location and purpose

Answer 4

white of the eye, continuous with the cornea

Question 5

What is the lens? location and purpose

Answer 5

helps focus rays of light on the retina

Question 6

what is the retina? location and purpose

Answer 6

the internal lining of the rear two-thirds of the eye, the retina coverts images into electrical impulses, which are sent to the brain.

Question 7

What is the macula? location and purpose

Answer 7

the central area of the retina that is specialised for central vision

Question 8

what is the fovea? location and purpose

Answer 8

the visual image received by the fovea is at least distorted; marks the centre of the retina and the centre of the macula

Question 9

what is the optic nerve? location and purpose.

Answer 9

made up of axons of the retinal ganglion cells; carries impulses for vision from the retina towards the brain

Question 10

how many extrocular muscels are there in the eye?

Answer 10

3

Question 11

what electromagnetic wavelength can be detected by the human eye

Answer 11

400-700nm

Question 12

Flow of visual information in the retnia

Answer 12

photoreceptors –> bipolar cells –> ganglion cells

Question 13

why do we have a blind spot?

Answer 13

there are no photoreceptors, therefore the sensation of light can not occur.

Question 14

What is the side of the eye closest to the nose called? and then the other side

Answer 14

Nasal hemiretina & temporal hemiretina

Question 15

What side of your visual field is the blind spot on?

Answer 15

temporal hemiretinal

Question 16

What is the optic chasm?

Answer 16

Where the axons of the ganglion cells cross the midline

Question 17

Do the axons of the ganglion cells located in each temporal hemi-retina cross the optic chasim?

Answer 17

no

Question 18

What happens if the left optic nerve is cut?

Answer 18

left eye vision will be lost, resulting in a loss of left peripheral vision.

Question 19

what happens if the optic chasm is transected?

Answer 19

Peripheral vision is lost bilaterally

Question 20

what happens if the left optic tract is cut?

Answer 20

vision of the right hemifield will be lost completely. Homonymous hemianopsia

Question 21

what are the axons of the ganglion cells called?

Answer 21

the optic nerve before they cross the optic chassim
optic tract after the optic chiasm

Question 22

where do the axons of the optic track project too?

Answer 22

Superior colliculus?
Thalamus (Geniculate nucelus)

Question 23

The retinotectal pathway

Answer 23

retina –> superior colliculus

Question 24

Retinogenisulostriate pathway

Answer 24

retina –> thalamus –> primary visual cortex

Question 25

What visual information does the right LGN track receive? then the left track

Answer 25

left, then right. oppisote

Question 26

is the LGN retnotopically mapped?

Answer 26

yes

Question 27

is the Primary visual cortex retinotopically mapped?

Answer 27

yes

Question 28

cortical vision pathway

Answer 28

retina
LGN
primary visual cortex in the occipital love
extrastriate cortex in the occipital, temporal and parietal lobes

Question 29

What happens when TMS is distributed over the primary visual cortex?

Answer 29

elicit light sensations in the absence of any stimuli

Question 30

What did the study on ecstasy and V1 excitability show?

Answer 30

The goal was to measure the excitability of the primary visual cortex and make comparisons.

Results 1: ectacy group had a significantly lower phosphine threshold than participants in the control group. Negatively correlated with phosphine threshold.

Results 2: phosphene threshold of participants who had hallucinations was significantly lower than the phonsoehen threshold of participants who did not hallucinate.

Question 31

what is the ventriloquist illusion?

Answer 31

mislocalisation towards a synchronous but spatially discrepant visual event