Unit 2-5

Question 1

Light made up of

Answer 1

Photons

Question 2

When light interacts with substance (3)

Answer 2

1. Reflected
2. Absorbed
3. Refracted (bent)

Question 3

Eye anatomy (5)

Answer 3

1. Retina
2. Cornea
3. Lens
4. Ciliary muscles
5. Fovea

Question 4

Retina

Answer 4

Layer of neurons at the back of eye that transduce light

Question 5

Cornea

Answer 5

Transparent outer layer of the eye that refracts light to focus it onto the retina

Question 6

Lens

Answer 6

Part of the eye that further refracts light on its way to the retina, capable of changing shape to adjust focus of the image

Question 7

Ciliary muscles

Answer 7

Muscles that change the shape of the lens

Question 8

Fovea

Answer 8

Area of the retina where visual acuity/sharpness is the highest

Question 9

Myopia

Answer 9

Nearsighted, eyeball lengthens and redacted light falls short of retina

Question 10

retina photoreceptors and the pigments

Answer 10

1. Rods (pick up low light, insensitive to color, pigment = rhodopsin)
2. Cones (detect color, less sensitive to low light, pigments = 3 cone opsin - basis of color)

Question 11

Rods and cones synapse on

Answer 11

Bipolar cells, which turn on ganglion cells (axons form optic nerves)

Question 12

Range fractionation

Answer 12

Handling different threshold of light by different receptors

Question 13

Photoreceptor adaptation

Answer 13

Each receptor neuron can adjust to ambient levels of light, allowing it to respond sensitively to changes

Question 14

Photoreceptors respond to light with

Answer 14

Hyperpolarization (reduces amount of transmitter released), rods and cones release NTs in the dark

Question 15

Optic disc

Answer 15

Blind spot in vision field, where blood vessels and optic nerve exit eyeball

Question 16

Visual processing pathways (5)

Answer 16

1. Optic nerves crosses midline and heads to contralateral brain (optic chiasm)
2. Retinal ganglion cells project to lateral geniculate nucleus of the thalamus
3. From thalamus to optic radiations (projections can out)
4. Primary visual cortex/ striate cortex (V1) (receives sensory input)
5. Secondary visual cortex/ extrastriate cortex (V2-V5) (sensitive to motion)

Question 17

How does visual system encode? (3)

Answer 17

1. Intensity (some bipolar cells respond to light, others dark)
2. Location (some bipolar and ganglion cells respond to stimulus in center of receptive field, while some respond to surrounding areas)
3. Direction (some cells are directional, respond to different orientations and directions of movement)

Question 18

V5

Answer 18

Motion detection (medial temporal area, MT)

Question 19

Color vision

Answer 19

• Brain compares info from different photoreceptors to interpret color
• photo pigment opsin in cones have peaks and broad ranges to sensitivity
• brain compares their response to determine color

Question 20

Color blindness

Answer 20

Absence of one type of cone (s - blue, m - green, L - red)