Rod Cells

• Where are photoreceptors (light receptors) found?

  On the retina.
• What are the two types of photoreceptors?

  Rods and cones.
• How do rods and cones create a nerve impulse?

  They conserve light energy into electrical energy.
• What can't rod cells do?

  Distinguish different wavelengths of light.
• Why do rod cells see images in black and white?

  As they can't distinguish between different wavelengths of light.
• What photoreceptor is more numerous?

  Rods.
• What do rod cells respond to and why?

  Light of low intensity due to many rod cells being connected to a singular bipolar cell, which further connects to one sensory neuron.
• Why is summation from rod cells favourable?

  It gives a greater chance of the threshold value being exceeded to create a generator potential.
• What is the pigment in rod cells called?

  Rhodopsin.
• How does low-intensity light cause an action potential in rod cells?

  the low-intensity light energy is enough energy to break down rhodopsin for the threshold to be met.
• What is a disadvantage to rod cells?

  They give low visual acuity meaning two light sources close together cannot be seen as separate.