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Why are there no blood vessels in the living epidermis?
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human skin
Human skin, whose cells are generated continuously by the body, serves as a protective barrier between the inside of the human body and the environment.
The living epidermis does not contain blood vessels because it is an avascular tissue that relies on the underlying dermis for nourishment.1
Instead of direct vascular supply, the epidermis receives necessary nutrients and materials through diffusion from the blood vessels located in the dermis below. This process is facilitated by the structural organization of epidermal cells; they are connected by specialized surfaces called desmosomes, which create a zipperlike contact between cells. While these connections hold the cells together, they also maintain fluid-filled spaces between the contact areas, allowing nutrient-rich fluids to seep upward from the dermis to sustain the living cells of the epidermis.12