What does integumentary system include?

The integumentary system is composed of the skin, hair, nails, and sweat glands. It works to protect the body from the external environment, regulate body temperature, and excrete waste products. The skin is the largest organ in the body and is composed of three layers: the epidermis, the dermis, and the hypodermis. The epidermis is the outermost layer of the skin and is made up of keratinized cells. The dermis is the middle layer of the skin and is composed of connective tissue, blood vessels, and nerves. The hypodermis is the innermost layer of the skin and is composed of fat cells. Hair is found all over the body and helps to insulate the body and protect it from the sun. Nails are found on the fingers and toes and help protect them from damage. Sweat glands are found all over the body and help to regulate body temperature by releasing sweat.