Vision

Question 1

Light

Answer 1

electromagnetic radiation visible to eyes

Question 2

wavelength

Answer 2

spatial period of the wave

Question 3

amplitude

Answer 3

How high the wave moves

Question 4

Frequencey

Answer 4

How sign waves travel across time

Question 5

What is the visual spectrum for humans?

Answer 5

400-700nm

Question 6

Pupil

Answer 6

dark hole in the center of the iris that allows light to enter

Question 7

iris

Answer 7

correlates with the pupil and light

Question 8

cornea

Answer 8

Protects the eye

Question 9

aqueous humor

Answer 9

its a fluid. behind cornea but in front of the lens. supports the lens.

Question 10

Vitreous

Answer 10

takes away waste and its a jelly like substance

Question 11

fovea

Answer 11

indent and a point on the central focus where information is trying to get to.

Question 12

pigment epithelium

Answer 12

behind the retina at the end of the rods.

Question 13

optic nerve

Answer 13

mainly axons are here and the information is taken to the brain

Question 14

blind spot

Answer 14

occurs where the optic nerve leaves the eye

Question 15

Explain the Image formation of the Eye

Answer 15

The eye collects light rays and reflects it off objects in the environment then focuses them onto the retina to form images.

Question 16

To the image information of the eye, how do the eye structures contribute to this?

Answer 16

The cornea refracts, the lens helps and the pupillary light reflex also accommodates this.

Question 17

How much does the cornea refract during the image formation of the eye?

Answer 17

Refracts about 60%

Question 18

How does the lens accommodate the image formation of the eye?

Answer 18

The lens adds more refraction for closer objects. about. 20 inches and 20 feet.

Question 19

Explain how the pupuillary light reflex helps the image formation of the eye?

Answer 19

The retina and the neurons connect to the brain stem which control the iris muscles.

Question 20

consensual

Answer 20

voluntary reflex correlated with involuntary reflex

Question 21

Constriction

Answer 21

increasing with depth of focus

Question 22

Visual field

Answer 22

how much you can see with your eyes, they overlap

Question 23

Visual acuity

Answer 23

how clear you can see something. how sharp the image is.

Question 24

Horopter line

Answer 24

locus of points in space that yield single vision

Question 25

photoreceptors

Answer 25

light sensitive cells in retina >bipolar cells> ganglion cells that carry output from retina

Question 26

Horizontal Cells

Answer 26

Talk to the rods and cons

Question 27

amacrine cells

Answer 27

talks to the ganglion cells

Question 28

scotopic

Answer 28

rods

Question 29

phototopic

Answer 29

cones

Question 30

How many photopigments are in rods?

Answer 30

only one

Question 31

When do photoreceptors depolarize?

Answer 31

in the dark, (dark current)

Question 32

Are cones sensitive to different wavelengths ?

Answer 32

yes

Question 33

What happens in phototransduction in rods?

Answer 33

Photoreceptors receive 1 photon of light then the light hits pigment(rhodopsin) and bleaches it. As rhodopsin bleaches the photo-receptor it actives the all transretinal and that activates transducin(G-protein). Then for every 1 transentinal we get 500 transducins. Transducins activates cGMP phosphodiesterase(pde). PDE deactivates cGMP and it decreases CGMP and decreases leads to closed the NA+ channels. hyperpolarizes the cell which decreases release of neurotransmitter. This process is the a csascade that amplifies one photon of light so that rods are very sensitive to light.

Question 34

What happpens in phototransduction in cones?

Answer 34

Rods can become saturated during the bright daylight. They reach a point where increased light no longer affects them.(they are all bleached out). So in the daylight, we use more cones since they need more light to bleach them. this is similar to rods but just a differnt type of opsin.

Question 35

NM for blue

Answer 35

420nm

Question 36

NM for green

Answer 36

530nm

Question 37

Nm red

Answer 37

560nm

Question 38

Are cones denser in the fovea?

Answer 38

Yes

Question 39

Are rods denser outside foveal region?

Answer 39

Yes

Question 40

What is the Young-Helmholtz Trichromatic Theory?

Answer 40

Brain assigns colors based on a comparsion of the readout of three cone types: red,green and blue, when all types of cones are equally active, we perceive white.