Ch. 50 - Sensory & Motor Mechanisms: Photoreceptors and Vision

Question 1

what are light detecting organs?

Answer 1

a collection of photoreceptors that respond to light and shadow

Question 2

what are compound eyes?

Answer 2

eyes that sense changes in light at high frequency; have more cones and can thus see more colours

Question 3

what is a single lens eye?

Answer 3

mammalian eyes with a pupil and layers of photoreceptors, using various methods to focus the lens when needed

Question 4

what is the structure of the sclera?

Answer 4

the “whites” of the eye - the hard structural framework

Question 5

what is the function of the sclera?

Answer 5

to provide the shape of the eyeball

Question 6

what is the structure of the cornea?

Answer 6

the cornea is the transparent covering of the eyeball

Question 7

what is the function of the cornea?

Answer 7

to protect the eye, and refract / bend light

Question 8

what is the structure of the choroid?

Answer 8

the choroid is a highly vascular pigmented layer, covering much of the eyeball

Question 9

what is the function of the choroid?

Answer 9

to provide blood supply to the eyeball, and absorb any stray light

Question 10

what is the structure of the iris?

Answer 10

the iris is a muscular ring with a hole in the middle - the pupil

Question 11

what is the function of the iris?

Answer 11

to contract or relax, regulating the amount of light that can enter the eyes

Question 12

what are the ciliary muscles?

Answer 12

a sphincter-like muscular ring around the eyes

Question 13

what is the function of the ciliary muscles?

Answer 13

to regulate the shape of the lens, and allow the lens to fatten/thicken

Question 14

what are suspensory ligaments?

Answer 14

bands that regulate the shape of the lens along with the ciliary muscles

Question 15

what is the function of the suspensory ligaments?

Answer 15

regulate the shape of the lens by…
contracting: “fattening the lens” [up close vision]
relaxing: thinning the lens, distance vision

Question 16

what is the lens?

Answer 16

a transparent and elastic disc of proteins within the eye

Question 17

what is the function of the lens?

Answer 17

to refract light into the eye
[refracts light more when thick than flat]

Question 18

what is the retina?

Answer 18

the part of the eye containing the photoreceptors and other neurons

Question 19

what is the function of the retina?

Answer 19

to transduce light signals into electrical signals so the brain can understand them

Question 20

what are the three types of cone cells found in humans?

Answer 20

red, green, and blue

Question 21

where are cone cells located within the eye?

Answer 21

all cone cells are concentrated in a region called the fovea centralis

Question 22

what type of vision do cone cells provide?

Answer 22

highly detailed vision - you can’t read this flashcard out of your peripheral vision because there’s no cones there

Question 23

what are rod cells?

Answer 23

cells that cannot see colour, but assist in night vision and sensing motion in the peripheral vision

Question 24

how is visual stimuli sent to the brain? (what nerve, what lobe)

Answer 24

the optic nerve sends visual information to the occipital lobe