This field is similar to that of Figure 9.3, but the keratinocytes of the basal and polyhedral cell layers contain pigment granules of melanin (arrows). These brown granules accumulate in the cytoplasm next to the nuclei. Located among the basal cells, the melanocytes, which produce the pigment granules, cannot be identified in this section. These melanin granules, once secreted by the melanocytes, are endocytosed by the keratinocytes.

The following cell layers of the epidermis are labelled:

• Basal layer, or stratum basale (A)
• Polyhedral cell layer, or stratum spinosum (B)
• Granular cell layer, or stratum granulosum (C)
• Cornified cell layer, or stratum corneum (D)

Stain: H–­­E
Magnification: ×900