and the most visible. The main function of the skin
is to act as a barrier, protecting the warm moist
internal environment from the essentially hostile,
dry and cool external environment in which we
live. It is a common belief that the skin acts as a
total barrier to the penetration of external substances.
In fact, it is permeable to many substances,
including perfumes and dyes with which we may
be in frequent contact.
Apart from protection, the skin plays critical roles
in the control of body temperature and blood pressure.
It also has endocrine functions and contains
numerous sensory receptors (Box 1). The condition
of the skin often reflects underlying disease processes.
It is important that nurses observe and attend to
patients' skin. An understanding of the structure
and physiology of the skin enables nurses to assess