A small gland in the skin of a mammal
that secretes a salty fluid solution (sweat). Excess body heat causes the
sweat to evaporate, which brings about cooling. Sweat glands are formed
from the epidermis but project deep into
the dermis. They occur over most of the body
surface in humans and other higher primates
but have a more limited distribution in other mammals. Dogs, for example,
have very few sweat glands, and those mostly on the pads of the feet.