Physiology · Special Senses

Photochemistry of vision and dark adaptation

5 min read

Definition

  • Phototransduction is the conversion of light energy absorbed by retinal photopigments into a hyperpolarizing photoreceptor potential in rods and cones.
  • Rhodopsin, the rod photopigment, has peak spectral sensitivity at 500 nm.

Structure of Photoreceptors

  • Rod outer segments contain stacked membrane disks bearing rhodopsin; cone outer segments are membrane infoldings bearing one of three cone pigments.

Structure of rod and cone photoreceptors