Topic overview

Start with the big picture

Physiology asks how living systems function, complementing anatomy’s focus on what structures are and where they are located. Its scope spans molecular pathways, cells, tissues, organs, systems, and the whole organism. A central theme is homeostasis: the coordinated regulation that maintains a stable internal environment amid changing conditions. Feedback control and adaptive responses help explain how physiological variables are monitored and adjusted. The discipline draws on physics and chemistry, scientific experimentation, and mathematical modeling to investigate these processes. By linking normal function to the consequences of dysfunction, physiology provides a foundation for pathophysiology and informs fields such as diagnosis, pharmacotherapy, anesthesiology, and critical care.