Hair

The cortex is the main body of the hair composed of elongated and fusiform (spindle-shaped) cells. It may contain cortical fusi, pigment granules, and/or large oval-to-round-shaped structures called ovoid bodies. Cortical fusi in this image are irregular-shaped airspaces of varying sizes. They are commonly found near the root of a mature human hair, although they may be present throughout the length of the hair.

Image courtesy of Microscopy of Hair Part 1: A Practical Guide and Manual for Human Hairs; Forensic Science Communications.