Chapter 10 Pt. 2 (Part 1)

Question 1

what is the significance of the fovea?

Answer 1

straight back

high cone density = higher acuity, accuracy

cones = color

Question 2

what is the significance of the optic disk of the eye?

Answer 2

no image can be created but the brain fills it in

Question 3

how does the eye refract light in order to focus on distant and near objects? (focal point)

Answer 3

changes focal point by

FAR OBJECT:
ciliary muscle: relaxed
zonular fibers: tight
lens: big

NEAR OBJECT:
ciliary muscle: contracted
zonular fibers: slack
lens: smaller

Question 4

what is the role of the cornea in focusing?

Answer 4

refractive ability remains constant because the cornea curvature cannot be changed

Question 5

what is the role of the lens in focusing?

Answer 5

refractive ability can be altered by changing the curvature of the lens to focus

Question 6

what is the role of the ciliary muscle in focusing?

Answer 6

change refractive index of lens

Question 7

what is the role of the zonular fibers in focusing?

Answer 7

change refractive index of lens

Question 8

when light from an image hits the back of the eye, the image is actually upside down, but we don’t see everything upside down. why?

Answer 8

our brain corrects the image

Question 9

what do rods and cone cells have in common?

Answer 9

they are photoreceptors that contain photopigment

Question 10

what is photopigment? aka what does it do?

Answer 10

absorb light

Question 11

what cells serve as connector neurons to link photoreceptors and retinal ganglion cells?

Answer 11

bipolar cells

Question 12

what is the role of bipolar cells?

Answer 12

serve as connector neurons to link photoreceptors and retinal ganglion cells

Question 13

what do horizontal cells do?

Answer 13

modulate photoreceptor stimulation of bipolar cells

Question 14

modulate photoreceptor stimulation of bipolar cells

Answer 14

horizontal cells

Question 15

what do amacrine cells do?

Answer 15

modulate bipolar cell stimulation of retinal ganglion cells

Question 16

modulate bipolar cell stimulation of retinal ganglion cells

Answer 16

amacrine cells

Question 17

retinal ganglion cells are the only neural cells in the eye that can generate ____, all the others only fire ____. why?

Answer 17

AP

graded potentials

no voltage-gated Na+ channels

Question 18

what is the advantage of dilating the pupils?

Answer 18

lets more light into the eye. more light means you can interpret the environment better

Question 19

what is the definition of refraction? what is it used for?

Answer 19

bending light. to bring objects into focus.

Question 20

increase lens curvature (thickness) makes the lens _____ in order to ?

Answer 20

more refractive

focus on near objects

Question 21

decrease lens curvature (thickness) makes the lens ____ in order to ?

Answer 21

less refractive

focus on distant objects

Question 22

how to focus on near objects?

Answer 22

increase lens curvature

Question 23

how to focus on far objects?

Answer 23

decrease lens curvature. relaxed ciliary muscle is default.

Question 24

what is near-sightedness

Answer 24

lens bends light in too much

Question 25

what is far-sightedness

Answer 25

lens can't bend light in enough

Question 26

what is astigmatism

Answer 26

light gets focused at multiple sites on the retina

Question 27

what cell released GABA when depolarized?

Answer 27

horizontal and amacrine cells

Question 28

horizontal cells modulate ___ potentials sent from _____ to _______

Answer 28

graded potentials photoreceptors bipolar cells

Question 29

what do rods have that make them more sensitive to light?

Answer 29

larger outer segment

Question 30

what is the significance of a larger outer segment in rods?

Answer 30

more sensitive to light

Question 31

what is the significance of the smaller outer segment in cones?

Answer 31

less sensitive to light

Question 32

what makes cones less sensitive to light

Answer 32

smaller outer segment