The integument, commonly called skin, forms the outer covering of the body, and functions in

• Protection,
• Temperature regulation,
• Excretion,
• Sensation,
• Vitamin D production and
• Artistic medium for tattoos

The skin consists of several layers:

• The surface epithelial layer, the epidermis, and
• An underlying connective tissue layer, the dermis.
• The subcutaneous layer (also known as the hypodermis or superficial fascia), is a connective tissue layer attaching skin to structures beneath it.

Thus, skin is considered an organ, and in fact is the largest organ of the body.