What does it mean that the epidermis is described as avascular?

The description of the epidermis as avascular means that it lacks blood vessels. This characteristic is essential for understanding how the epidermis functions and receives nutrients. Since the epidermis is the outermost layer of the skin, it is primarily responsible for protection and does not require a direct blood supply. Instead, it obtains nutrients and oxygen through diffusion from the underlying dermis, which is vascular and contains blood vessels. This avascular nature also helps to prevent the loss of water and reduces the risk of bleeding when the skin is superficially damaged. Understanding this distinction is crucial for comprehending skin physiology and the healing processes that occur when the epidermis is injured.