Skin appendage
Skin appendages (or adnexa) are skin-associated structures that serve a particular function including sensation, contractility, lubrication and heat loss. In humans, some of the more common skin appendages are hairs (sensation, heat loss, filter for breathing, protection), arrector pilli (smooth muscles that pull hairs straight), sebaceous glands (secrete sebum onto hair follicle, which oils the hair), sweat glands (can secrete sweat with strong odour (apocrine) or with a faint odour (merocrine or eccrine)), and nails (protection). Skin appendages are derived from the skin, and are usually adjacent to it. Types of appendages include hair, glands, and nails