Biomedical Engineering Reference
In-Depth Information
39.1 Introduction
The skin, the largest organ in the body, primarily serves as a protec-
tive barrier against the environment. Skin injuries, including burns
and infections, are among the most complex and harmful physical
injuries to evaluate and manage.
1
Loss of integrity of large portions
of the skin may result in significant disability or even death. Skin
replacementhasbeenachallengingtaskforsurgeonseversincethe
introduction ofskin grafts by Reverdin in 1871.
The skin consists of the epidermis and the dermis, with a com-
plex nerve and blood supply. Figure 39.1 shows a schematic of
requirementstocreateafullyfunctionalskinandthestructureofthe
skin. The adult skin is composed of two distinct layers, the epider-
mis and the dermis. The thin epidermis comprises rapidly dividing
keratinocytes, which produce keratin, a strong structural protein.
The topmost layer of the epidermis is the stratum corneum, a thin
watertightlayerofdead,flattenedcells.Thethickerdermis,situated
below the epidermis, is a complex association of fibroblasts and the
extracellular matrix (ECM), accounting for the skin's mechanical
integrity and elasticity. The skin's blood vessels, nerve fibers, and
lymphaticsallresidewithinthislayer.Theepidermisisnourishedby
diffusionofsmallmoleculesfromthedermis.Theskin'sappendages,
Figure 39.1.
Schematic of requirements to create a fully functional skin.
See also Color Insert.
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