E.2.4 Compare rod and cone cells.

Photoreceptors are the rods and cones

Both rods and cones synapse with their bipolar neurons

Rod cells are sensitive to light. They receive the stimulus of light, even dim light, and synapse with a bipolar neuron

Cone cells are activated by bright light. They receive the stimulus of bright light and synapse with a bipolar neuron

Bipolar neurons: cells in retina which carry impulses from a rod or cone cell to a ganglion cell of the optic nerve. They are called bipolar because they each have 2 processes extending from the cell body.

Ganglion cells are the cell bodies of the optic nerve. They synapse with the bipolar neurons and send the impulses to the brain.

Rods	Cones
Low/Dim light	Bright light
1 type of rods found in retina. It can absorb all wavelengths of visible light	3 types of cones found in retina. 1 can absorb red light, 1 blue and 1 green
Impulses from a group of rod cells pass a single nerve fibre (Ganglion axon) in the optic nerve	Impulse from a single cone cell passes to a single nerve fibre in the optic nerve