Final answer:
The human skin is composed of the epidermis, dermis, and hypodermis, with each layer serving distinct functions from protection to support and nutrient supply to the skin.
Step-by-step explanation:
The layers of the human skin consist primarily of the epidermis, dermis, and subcutaneous tissue, commonly referred to as the hypodermis. The epidermis is the outermost layer, which is relatively thin, comprises keratin-filled cells and lacks a blood supply. Its function is to serve as a protective barrier against water loss and pathogen invasion. Just below it lies the dermis, a substantially thicker layer containing a variety of structures, including blood vessels, sweat glands, hair follicles, lymph vessels, and sebaceous glands that secrete lipids. The deepest layer is the hypodermis, which consists mainly of connective tissue and stores approximately 50 percent of the body's fat. It also anchors the dermis to the underlying bone and muscle and provides the dermis with nerves and blood vessels.