What is the Difference Between Keratinocytes and Corneocytes?

🆚 Go to Comparative Table 🆚

Keratinocytes and corneocytes are both types of cells found in the skin, but they have distinct differences in their structure and function:

Keratinocytes:

  • Living cells that make up the majority of the epidermis, the outermost layer of the skin.
  • Formed at the basal layer just above the dermis and are metabolically active.
  • Serve important functions, including the production of the structural protein keratin.
  • As keratinocytes progress through the epidermis, they enter the stratum granulosum, where they are transformed into nonviable corneocytes before being shed in the stratum corneum.

Corneocytes:

  • Dead cells without nuclei and cytoplasmic organelles.
  • Terminally differentiated keratinocytes that compose most of the stratum corneum, the outermost layer of the epidermis.
  • Contain a highly insoluble cornified envelope within the plasma membrane and lipids (fatty acids, sterols, and ceramides) released from lamellar bodies within the epidermis.
  • Regularly replaced through desquamation and renewal from lower epidermal layers.

In summary, keratinocytes are living cells responsible for producing keratin, while corneocytes are dead cells in the stratum corneum that serve as a protective barrier against harmful substances in the environment.

Comparative Table: Keratinocytes vs Corneocytes

Here is a table summarizing the differences between keratinocytes and corneocytes:

Feature Keratinocytes Corneocytes
Definition Keratinocytes are living cells that originate in the stratum basale of the skin and are responsible for producing the structural protein keratin. Corneocytes, also known as squames, are terminally differentiated keratinocytes that have undergone the process of keratinization and are found in the stratum corneum.
State of Differentiation Keratinocytes are metabolically active, with normal constituents such as a nucleus and cytoplasm. Corneocytes are nonviable and do not contain a nucleus or organelles.
Size and Shape Keratinocytes are approximately 30 µm in diameter and 0.3 µm thick. Corneocytes have a larger surface area in the horizontal direction but are only about 0.3 µm thick.
Composition Keratinocytes produce keratin as they move through the epidermis. Corneocytes are composed of a cornified envelope and a keratin-filled interior.
Layer in Skin Keratinocytes are found in the epidermis, which is the outermost layer of the skin. Corneocytes form the stratum corneum, which is the outermost layer of the epidermis and acts as a protective barrier.
Lifespan Keratinocytes undergo a complex process of differentiation to form the stratified stratum corneum layer of the skin, which takes on average 14 days. The lifespan of a corneocyte is about two to three weeks.

In summary, keratinocytes are living cells responsible for producing keratin, while corneocytes are dead cells formed from keratinocytes in the stratum corneum, which serve as a protective barrier for the skin.