The Cornified Layer (Stratum Corneum of the Epidermis)

• The cornified layer (Stratum Corneum): by the time cells reach this layer the whole of the cytoplasm (cell’s “empty area”) has become a dense network of keratin filaments, interspersed with granules full of lipids.
  • No more nuclei are present; indeed about halfway up the nucleus is broken down and reabsorbed.
  • Although the epidermal surface appears disorganized, removing the “loose cells” (tape stripping) a striking geometric arrangement is revealed: the squames have a regular hexagonal shape and overlap slightly with each other. Arranged together, they form a 14 sided solid, this ensures (like bubbles in foam) a maximum surface coverage with the minimum amount of material. This also ensures individual “progressive” shedding of cells which prevent bacteria from penetrating.
  • Epidermal Skin Cells (Keratinocytes) which reach the Stratum Corneum are called corneocytes. There are 1000 corneocytes per square millimeter, and on average a humen being has a skin surface of just under 2 square meters. This leads to a turnover of around 2000 million cells each day. The shed skin cells make up about 60% of household dust. 

Reference: The Cell: A Very Short Introduction. Allen T. Oxford University Press