The largest organ system; includes the skin and all structures derived from it, including the hair and nails.
Skin and its appendages: nails, hair, sebaceous glands.
The skin and its derivatives (hair, nails) and the subcutaneous tissue.
The skin and its accessory organs, such as the oil and sweat glands, sensory receptors, hair, and nails; serves as a protective covering and helps regulate the body’s temperature.