Skin (anatomy)

Skin is the body's largest organ, serving as a protective barrier that covers and guards internal tissues and organs. It consists of three main layers: the outer epidermis, which provides a waterproof surface and contains cells that produce pigment; the underlying dermis, rich in collagen and elastin fibers that give skin strength and elasticity, and housing blood vessels, nerves, and glands; and the deeper subcutaneous tissue, made of fat and connective tissue that insulates and cushions the body. Skin also plays key roles in regulating temperature, sensing touch, and producing vitamin D.