In the simplest of terms, physiology is the study of function of components within a living organism. Another way of defining physiology is to say that it is the study of how living organisms maintain homeostasis .
Homeostasis is an important concept in physiology.
In essence, this term refers to the steady state conditions within a living organism that must be constantly maintained in order for the organism to survive and reproduce. In large multicellular organisms such as humans, this is quite a task, and the various organ systems within our bodies must operate efficiently in order to maintain an internal environment that will allow all of the cells and tissues in our bodies to survive as a whole. Every individual cell, no matter where it is located within the organism, has certain basic requirements for energy, oxygen, water, minerals, and other basic necessities of life. To meet these needs, homeostatic processes are working continuously to maintain the steady state of the fluid that surrounds each and every cell in the body. In addition to these needs, there must be systems for ingestion and digestion of nutrients, and systems for elimination of the toxic waste products of metabolism.