Eye

Question 1

Visual acuity

Answer 1

The ability to tell apart 2 points that are close together. (Cones have goood visual acuity each cone connected to one bipolar neurone)

Question 2

Retinal convergence

Answer 2

Several rods are connected to one bipolar cell, so summation occurs ie. the effects of neurotransmitters released from many neurones are added together

Question 3

Pigment that rod cells contain

Answer 3

Rhodopsin

Question 4

Pigment that cone cells contain

Answer 4

Iodopsin

Question 5

Which photoreceptors give retinal convergence and when is that an advantage?

Answer 5

Rods. Having more than one rod to each bipolar neurone allows spatial summation which enables us to see in dim light.

Question 6

How are rods and cones distributed on the retina?

Answer 6

Rods at periphery and cones are near the fovea

Question 7

Why is there a blind spot?

Answer 7

There are no photoreceptors at the point where the optic nerve enters the brain

Question 8

Why can you see colours other than red green and blue?

Answer 8

The 3 types of cone are sensitive to different wavelengths of light. At a particular wavelength each type will absorb a different amount of light so will send more/fewer impulses to the brain. The combination of this enables different colours to be seen.