The skin is our outer covering. In an adult, it covers an area of around two square meters (20 square feet) and weighs around 14 kilograms (30 pounds). This makes it the largest, and also most nerve-rich organ in the human body. Its thickness and structure can vary greatly depending on the body region, and our entire organism depends on it functioning well. That’s because it has several important tasks to fulfill, for example to regulate body heat, and to act as a protective wall against infections and dehydration. The skin also plays an important role in interpersonal relationships by perceiving and expressing feelings. In short, it is indispensable to humans.
Epidermis: Protective coat and immunological organ
The epidermis protects the organism from harmful external influences and prevents microorganisms from entering the body. The cells of the epidermis are continuously replenished from the bottom-most cell layer. At the end of their lifecycle, they detach themselves as tiny flakes from the surface of the skin.
Dermis: Network and transport system
Below the thin epidermis lies the more robust dermis. It is very supple. Its elasticity and tear-strength comes from a network of collagen and elastin fibers. Embedded within it is a widely branched network of blood and lymph vessels. This circulatory system regulates, amongst other things, the temperature at the skin – it acts, so to speak, as an air conditioning system for the body. The dermis also contains thousands of nerve fibers. These enable us to sense touch, pain, temperature and even itchiness.
Subcutis: Energy store and protection against the cold
The subcutis comprises mainly fatty tissue, which stores energy, protects against the cold, and acts as a cushion. The fat cells are embedded in a loose network of connective tissue that is permeated by larger nerve fibers and a second network of blood vessels. Hair follicles, and also the sebaceous and sweat glands, extend down into this skin layer.
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On this page you will learn more about your skin and how it works. Even though we can’t see it from the outside, the largest organ of the human body consists of three interconnected layers.
The layers are called:
Your sebaceous glands, hair and nails are also part of the skin and are made from specialized skin cells.