The document summarizes the structure and function of the integumentary system. It describes the two main layers of the skin - the epidermis and dermis. The epidermis contains keratinocytes, melanocytes, Langerhans cells, and Merkel cells. The dermis lies underneath and contains blood vessels, nerves, hair follicles, and sebaceous and sweat glands. The skin and its appendages act as a protective barrier and play roles in temperature regulation, sensation, and waste excretion.