What is the outermost layer of the skin called?

The outermost layer of the skin is called the epidermis. It serves as the first line of defense against environmental factors such as pathogens, chemicals, and physical injuries. The epidermis is composed primarily of keratinized squamous epithelial cells, which provide protection and contribute to the skin's barrier function. Additionally, this layer is responsible for the production of melanin, which determines skin color and provides some protection against UV radiation.

The epidermis is also involved in the process of skin regeneration, as it continuously sheds dead skin cells and replaces them with new ones produced by the underlying layers. This dynamic process is essential for maintaining healthy skin.

In contrast, the dermis is located beneath the epidermis and contains connective tissue, blood vessels, and hair follicles, while the hypodermis, also known as the subcutaneous layer, lies beneath the dermis and consists primarily of fat and connective tissues, serving as an insulator and cushion for the body. Understanding these layers and their functions helps clarify the unique role of the epidermis as the outer protective barrier of the skin.