ABSTRACT

Histologic examination of skin reveals relatively cuboidal cells at the base of the

epidermis (1). This is the replicative compartment and occasionally basal cells are

seen in the process of cell division. However, most of the cells in the basal layer

are quiescent and serve to anchor the epidermis onto the basal lamina, which is

a specialized interface between the epidermis and the dermis. Several layers of

cells immediately above the basal layer have a prickly or spiny appearance and are

collectively called the spinous layer. This appearance reflects the shrinkage of cell

bodies away from the many desmosomal plaques in these suprabasal layers.

Above the spinous cells are several layers of cells that contain dark granular

material. The grainy material is composed of several protein components, which

make up the keratohyalin granules. In the uppermost cells within this compartment

there are no nuclei.