Inner nuclear layer

Bipolar cells

The bipolar cells, by far the most numerous, are round or oval in shape, and each is prolonged into an inner and an outer process.

They are divisible into rod bipolars and cone bipolars.

• The inner processes of the rod bipolars run through the inner plexiform layer and arborize around the bodies of the cells of the ganglionic layer; their outer processes end in the outer plexiform layer in tufts of fibrils around the button-like ends of the inner processes of the rod granules.
• The inner processes of the cone bipolars ramify in the inner plexiform layer in contact with the dendrites of the ganglionic cells.

Connection types

Midget bipolars are linked to one cone while diffuse bipolars take groups of receptors. Diffuse bipolars can take signals from up to 50 rods or can be a flat cone form and take signals from seven cones. The bipolar cells corresponds to the intermediary cells between the touch and heat receptors on the skin and the medulla or spinal cord.