Photoreceptors

Question 1

Describe the roles of cones.

Answer 1

Cones are responsible for our ability to see colour, they work in high light intensity and give high acuity, meaning very detailed images.

Question 2

Describe the roles of rods.

Answer 2

Rods are responsible for black and white imaging, they work best in low light intensity so are highly sensitive and images are low detail.

Question 3

Why do cones give more detailed images than rods?

Answer 3

For every cone there is one receptor and one neurone so it can easily determine the different lights and signals to create a more detailed image. However, rods can be up to 250 per neurone so contribute to spatial summation and each cumulatively generates a signal.

Question 4

What is photobleaching?

Answer 4

Eyes have pigments in their eye where when light is shone on them turn white. Cones have iodopsin and rods have rhodopsin. When lights are turned off, rhodopsin levels rise, so you can see more detailed images in the dark.