Figure 6. Differences in mitochondria morphology between cones and rods in young and old C57BL/6 mice.

A. Representative electron micrograph of young inner segment showing mitochondria in rod and cone photoreceptors. The mitochondria in rods are condensed and electron dense while the mitochondria in the cones are relatively electron translucent. B. Representative electron micrograph from an old mouse at the level of the inner segment. There are fewer mitochondria in the cone of old mice and these are electron dense similar to those found in adjacent rods. Scale bar = 0.5 μm.