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Article: Skin
- Article from:
- Biology
- Author:
CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Skin
How is the skin, the largest organ in the body, constructed? The skin has two layers: the upper layer is the epidermis, and the lower layer is the dermis. Below the dermis is the hypodermis, or
subcutaneous
layer, composed of fat or other
connective tissue
.
The epidermis itself is an
epithelium
made up of sublayers. The outermost portion consists of many layers of flat, dead, dry epithelial cells called keratinocytes. Clearly this barrier of dead cells needs no blood supply. The waxy surface coating of these cells allows the skin to be waterproof and dry. In effect, the body surrounds itself with a hostile desert where few germs can live.
Living keratinocytes in the deepest ...