Sweat glands are small exocrine glands found in human skin that produce sweat, which is a watery fluid containing salts and other substances. They play an important role in thermoregulation, as they help to cool the body by secreting sweat onto the surface of the skin where it evaporates, taking heat away from the body's core. There are two types of sweat glands: eccrine glands and apocrine glands. Eccrine glands are found all over the body and produce a constant, light sweating to regulate temperature. Apocrine glands are found mainly in the armpits and groin area and produce a heavier, more oily sweat when the body is under stress or during physical activity.