Sebum is an important substance for the protection
of the skin.
(The skin is also known as the "integument",
Sebum is an oily substance secreted by sebaceous
glands into fine ducts
that convey the sebum to the surface of the skin where it emerges with
The functions of sebum include reducing the speed of
evaporation of water from the surface of the body, and also protecting
the skin (and
hence the body within) by its antibacterial effect.