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What happens to keratinocytes as they reach the stratum corneum?

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Learn how regenerative properties of the skin helps to protect the human body from the external environment — human skin Human skin, whose cells are generated continuously by the body, serves as a protective barrier between the inside of the human body and the environment.

As keratinocytes reach the stratum corneum, they undergo a process of transformation into dead, flattened cells known as corneocytes. During this transition, the cells lose their nuclei and most of their organelles, including the keratohyalin granules.123

These cells become progressively filled with keratin, an insoluble filamentous protein. Within the lower region of the stratum corneum, the spaces between these compacted, keratin-filled cells are filled with lipid (waxy) lamellae, which are derived from membrane-coating granules produced in the underlying epidermal layers. This lipid-rich matrix is essential for creating a barrier that prevents water loss and protects the body from environmental injury. Ultimately, these cells are continuously shed from the skin surface through a process called desquamation, as the desmosomes connecting them are enzymatically broken down.4132