The skin is the tissue designed to regulate temperature, secrete lubricants, and protect the body from harmful substances. It is one of the largest organs in the body and consists of two layers --- the epidermis and the dermis. Its three main functions are to protect, regulate, and sense.
It serves as the primary barrier of the body from impacts and pressure, variations in temperature, radiation and chemicals, and micro-organisms. It regulates body temperature through sweat and hair and is a reservoir for Vitamin D synthesis. As a sensory organ it has a network of nerve cells that detect and relay changes in the environment through heat, cold, touch, and pain.