Visual Anatomy of the Eye

Question 1

cornea

Answer 1

in front of the eye, sclerotic coat gives way to cornea

transparent cells that provide a medium for beams of incoming light rays to focus on fovea

Question 2

outermost portion of the cornea is known as the

Answer 2

conjunctiva

Question 3

lens

Answer 3

transparent tissue whose shape can be changed allowing for fine focusing of vision

Question 4

retina

Answer 4

back wall of eye containing photoreceptor cells (rods & cones) and other cells involved in visual transduction

Question 5

fovea

Answer 5

area on retina of greatest concentration of photoreceptor cells
-most vision occurs here
everything else is peripheral vision

Question 6

optic disk

Answer 6

blind spot, region of retina where ganglion cell axons exit, medial to fovea

Question 7

steps to visual transduction: 1. light interacts with retina

Answer 7

causes retna to isomerize from the 11-cis to the all-trans form

Question 8

steps to visual transduction: 2. all trans retinal forces opsin to change shape

Answer 8

leading to meta-rhodopsin 2

Question 9

steps to visual transduction: 3. meta-rhodopsin 2 binds a G-protein (transduction)

Answer 9

meta-rhodopsin decays after to opsin and all trans and is recycled before it can be used again

Question 10

steps to visual transduction: 4. tranducin releases GDP and binds to GTP

Answer 10

becoming activated

Question 11

steps to visual transduction: 5. active transducing stimulates the enzyme

Answer 11

cGMP phosphodiesterase

Question 12

steps to visual transduction: 6. phosphodiesterase activation leads to decreased

Answer 12

cGMP

Question 13

steps to visual transduction: 7. decreased cGMP leads to

Answer 13

closing of cGMP gated Na+ channesl

Question 14

steps to visual transduction: 8. net result is

Answer 14

hyperpolarization of rod cell

Question 15

primary visual cortex - two main visual pathways

Answer 15

1. M pathway

2. P pathway

Question 16

M pathway (mangocellular) gives rise to what?

Answer 16

dorsal visual pathway in the cortex?

Question 17

M pathway is involved in seeing things

Answer 17

MOVE and WHERE THEY ARE LOCATED in the visual field

motion, depth, crude form

Question 18

P pathway (parvocellular) gives rise to what?

Answer 18

ventral visual pathway in the cortex

Question 19

P pathway is involved in

Answer 19

OBJECT SHAPE IDENTIFICATION and COLOR IDENTIFICATION
fine form - positive and negative form
color - red, blue, green

Question 20

receptive fields

Answer 20

triangle means that light inhibits that area (off-center cells)
X means that light activates the area (on-center cells)

Question 21

Simple Cells have 3 features:

Answer 21

1. they respond to a specific point in the visual field
2. they have discreet excitatory and inhibitory zones
3. they have a specific axis of orientation

Question 22

retinotopy

Answer 22

topographic layout of the retina