Final answer:
The term for the outermost layer of skin is the epidermis, which is key for protection and lacks a blood supply, nerve endings, and is composed of keratinized cells.
Step-by-step explanation:
The Outermost Layer of Skin
The term that describes the outermost layer of skin is the epidermis. This layer serves as a critical barrier, protecting the underlying tissues. The epidermis is thin and is composed largely of epithelial cells which are filled with keratin, a tough fibrous protein. Interestingly, the epidermis lacks a blood supply, nerve endings, and other common structures present in deeper layers of the skin.
Beneath it, the dermis hosts several structures such as blood vessels, sweat glands, hair follicles, and sebaceous glands. The innermost layer, under both the epidermis and the dermis, is known as the subcutaneous tissue or hypodermis, which contains the fatty deposits of the body and serves as the attachment point for the skin to the underlying bone and muscle.
It's important to note the distinction between the epidermis as the outermost layer and the underlying layers that serve different functions. The epidermis not only protects against water and pathogen invasion but also is responsible for the generation of new skin cells. These new cells are produced in the innermost layer of the epidermis, and then move up to the surface, becoming keratinized and forming a tough outer barrier.