Human skin. Illustration of a section through human skin. On the surface is a protective layer of dead epithelial cells, here coloured brown. Below this is the living epithelium (pink), which is constantly replenished by the actively dividing basal membrane. Under the epidermis is the dermis (pale pink), a layer of connective tissue that contains blood vessels, glands and hair follicles. The hair seen here is attached to an erector muscle controlled by a motor nerve fibre (white). A sebaceous gland opens onto the hair, producing lubricating sebum to keep the skin supple. Below the dermis is subcutaneous fatty tissue (yellow).