Stratum disjunctum

With AHAs, the stratum disjunctum (SD), the outermost layer of the epidermis that makes the skin feel rough, flakes immediately. The skin, having lost its topmost layer, immediately feels softer to the touch. 

One of the skin s defenses against infection is neutralized by all peels the destruction of the stratum corneum makes the skin more permeable to microorganisms. The cells of the stratum disjunctum - the outermost cells in normal... 

The stratum comeum is the outermost layer of the epidermis and consists of several layers of completely keratinized, dead cells that are constantly desquamated (Figure 1.1 to Figure 1.4). This layer does not contain nuclei or cytoplasmic organelles. The density of the stratum comeum cell layer can vary depending on how the filaments are packed. The most superficial layers of the stratum comeum that undergo constant desquamation are referred to as the stratum disjunctum. 

In the outer 15 layers of the SC, corneocytes adhere to one another by rudimentary desmosomes - the corneosomes - (Chapman et al. 1991) and by the intercellular lipid bilayers bound tightly to ceramide 1 of the envelope, which work as the scaffold for these intercellular lipids (Schurer et al. 1991) and for their correct orientation along the surface of the corneocytes (Ponec et al. 1997). At the stratum disjunctum, ceramide 1 is probably hydrolyzed by ceramidases or surfactant-like lipids (Rawlings et al. 1994) and the desmosomes are degraded by humidity-dependent proteases, allowing the normal unicellular corneocyte desquamation (Rawlings et al. 1995 Rudikoff 1998). 

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