Photoreceptors

Question 1

What light-sensitive pigment is present in rod cells?

Answer 1

Rhodopsin

Question 2

What light-sensitive pigment is present in cone cells?

Answer 2

Iodopsin

Question 3

Where are rods distributed in the eye?

Answer 3

Peripheries of the retina except for the fovea and blind spot.

Question 4

What is retinal convergence?

Answer 4

The brain cannot distinguish between the separate sources of light that stimulated it. Rod cells give low visual acuity.

Question 5

How many different types of cone cells are there and what colour pigment?

Answer 5

Three different types of cone cells with either red, green, or blue iodopsin which absorb different wavelengths of light. The colour you see is the different proportions of iodopsin being broken down.

Question 6

Why do you have high visual acuity with cone cells?

Answer 6

Each cone cell connects to a bipolar cell, so the brain can distinguish between different sources of light.