stratum corneum
noun
stratum cor·ne·um
-ˈkȯr-nē-əm
: the outermost layer of the epidermis that consists of keratin-rich corneocytes connected by desmosomes and embedded in a matrix of lipids (such as ceramides and cholesterol) arranged in bilayers and that regulates skin permeability, maintains hydration, provides structural integrity, and acts as a protective barrier (as against UV radiation, pathogens, and toxins)
Note: In humans, the stratum corneum is typically 12 to 20 cell layers thick but may be over 50 layers thick in the soles of the feet and less than 9 layers thick on the eyelids. The outer layers are continually shed with one corneocyte cell layer typically sloughed off every day as desmosomes are enzymatically broken down.
The stratum corneum barrier relies predominantly on the extracellular matrix, where lamellar bilayers block the outflow of water into the environment … .—Peter M. Elias et al.
A primary function of the stratum corneum is to protect the underlying tissue from environmental injury.—Discover
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