What are the terminally differentiated keratinocytes that make up most of the outer layer of skin called?

The terminally differentiated keratinocytes that predominantly constitute the outer layer of the skin are referred to as corneocytes. These cells play a significant role in forming the stratum corneum, the outermost layer of the epidermis, which is essential for providing a protective barrier against environmental factors, pathogens, and moisture loss.

Corneocytes are essentially dead, flattened keratinocytes that are filled with keratin, a structural protein that contributes to the strength and resilience of the epidermis. Their composition and arrangement in the stratum corneum help maintain skin hydration and integrity.

In contrast, melanocytes are cells responsible for producing melanin, the pigment that gives skin its color, and they do not make up the outer layer of the skin. Fibroblasts are found in the dermis and are involved in the production of collagen and elastin, which provide skin structure and elasticity. Adipocytes are fat cells located primarily in the subcutaneous layer and serve to store energy and insulate the body. Hence, the distinction between these cell types highlights the specialized functions they perform in skin health and maintenance.