The document discusses the integumentary system and introduces four combining forms used when discussing this system: melan/o, seb/o, rhytid/o, and ichthy/o. It provides examples of medical terms built from each combining form and defines their meanings, such as hypomelanosis meaning abnormal skin pigment, sebaceous glands secreting the oil sebum, rhytidectomy being surgical removal of wrinkles, and ichthyosis referring to scaly or dry skin conditions. The integumentary system, largest organ system, includes the skin and its structures.