VISION

Question 1

retina

Answer 1

The light sensing

portion of the eye,

Question 2

WHAT DOES THE RETINA CONSIST OF?

Answer 2

photoreceptor cells (RODS AND CONES) and their
afferent neurons

Question 3

WHAT IS . Between the cornea and lens

Answer 3

anterior chamber

Question 4

WHAT IS INSIDE ANTERIOR CHAMBER?

Answer 4

fluid, called aqueous humor.

Question 5

POSITION OF POSTERIOR CHAMBER

Answer 5

between the lens and the

retina.

Question 6

WHAT POSTERIOR CHAMBER CONTAINS?

Answer 6

a gel called vitreous humor

Question 7

The pupil controls

Answer 7

the

amount of light entering the eye.

Question 8

WHAT DO The photoreceptor cells DO?

Answer 8

convert energy from the light into an electrical signal that is
processed by the brain and transformed into a perceived image.

Question 9

Ciliary muscles

Answer 9

encircle the perimeter of the lens and flatten the lens

when the muscles relax or make the lens more round when the muscles contract.

Question 10

WHAT DOES A lens that is more round DO?

Answer 10

allows the eye to focus on closer objects

Question 11

Retina. The retina contains two types of photoreceptor cells

Answer 11

the rods and cones

Question 12

WHAT ARE Photopigment proteins IN THE BACK OF MEMBRANE CALLED?

Answer 12

retinal, a derivative of vitamin A

Question 13

WHAT DOES RETINAL DO?

Answer 13

changes its conformation in response to a photon of Light

Question 14

WHAT ARE RODS?

Answer 14

Photoreceptor rod cells express rhodopsin photopigment protein and are
very sensitive to light

Question 15

RE RODS FOR NIGHT OR DAY VISION?

Answer 15

NIGHT

Question 16

TO HOW MANY BIPOLAR CELLS RODS PHOTORECEPTORS BIND TO?

Answer 16

1

Question 17

WHY ARE Cones USED FOR DAY LIGHT VISION?

Answer 17

BECAUSE THEY are less sensitive to light and so are used in conditions of
high levels of illumination.

Question 18

HOW MANY PHOTORECEPTORS TYPES IN RETINA?

Answer 18

TWO. RODS AND CONES

Question 19

WHAT PROTEIN DO CONES EXPRESS

Answer 19

opsins.

Question 20

HOW MANY BIPOLAR CELLS BIND A CONE?

Answer 20

Bipolar cells bind only one cone cell so there is high

resolution vision with cones

Question 21

HOW CONES PERCEIVE DIFFERENT WAVELENGTHS?

Answer 21

The three different opsins that are expressed by the three types of cones bind retinal in unique ways

Question 22

WHAT ARE THE 3 OPSINS SENSITIVE TO?

Answer 22

red, blue or green wavelengths of light

Question 23

HOW OPSINS DIFFERENTIATE COLORS?

Answer 23

red light from a red object primarily hyperpolarizes cones expressing redsensitive opsin. This activates red bipolar cells and ganglion cells. Colors other than
red, blue, or green are perceived when combinations of different cones are stimulated.
For instance, we perceive yellow when the red and green cones are both stimulated.