Which part of the epidermis does not have its own blood supply?

The epidermis does not have its own blood supply; instead, it relies on diffusion from the underlying dermis for nutrients and oxygen. Specifically, the outermost layer of the epidermis, known as the stratum corneum, is avascular and consists of dead keratinized cells that provide a protective barrier. The lack of blood vessels in the epidermis is essential for its function, as it allows for effective barrier formation without interfering with the skin's protective role.