Study of the functioning of living organisms or their constituent tissues or cells. Physiology was usually considered separately from anatomy until the development of high-powered microscopes made it clear that structure and function were inseparable at the cellular and molecular level. An understanding of biochemistry is fundamental to physiology. Physiological processes are dynamic; cells change their function in response to changes in the composition of their local environment, and the organism responds to alterations in both its internal and external environment. Many physiological reactions are aimed at preserving a constant physical and chemical internal environment (homeostasis). See also cytology.
This entry comes from Encyclopædia Britannica Concise.
For the full entry on physiology, visit Britannica.com.
Seen & Heard
What made you look up physiology? Please tell us what you were reading, watching or discussing that led you here.