Physiology is the branch of biology that deals with the functions of living organisms and the parts of which they are made. This scientific discipline covers a wide variety of functions, ranging from the cellular and below to the interaction of organ systems that keep the most complex biological machines running.
PTSD redirects here. For the album by Pharoahe Monch, see PTSD (album). Posttraumatic stress disorder (PTSD) is a mental disorder that can develop after a person is exposed to a traumatic event, such as sexual assault, warfare, traffic collisions, or other threats on a person's life.
PTSD is recognized as a psychobiological mental disorder than can affect survivors of not only combat experience, but also terrorist attacks, natural disasters, serious accidents, assault or abuse, or even sudden and major emotional losses.