When we speak of human physiology, we speak of the science of the mechanical, physical, and biochemical functions of human bodies, their organs, and the cells of which they are composed, with a primary focus at the level of organs and systems. This is closely related to the field of study of Anatomy; indeed anatomy, the study of form, and physiology, the study of function, are intrinsically tied and are studied in tandem as part of a medical curriculum.
To understand physiology is to understand Integration, Communication, and Homeostasis
The biological basis of the study of physiology, integration, deals with the overlap of many functions of the systems of the human body, as well as its accompanied form. It is achieved through communication which occurs in a variety of ways, both electrically as well as chemically, often with redundancy build in.
In terms of the human body, the endocrine and nervous systems play major roles in the reception and transmission of signals which integrate function. Homeostasis is the process by which the body maintains a stable internal environment, or one of “similar condition” as described by Walter Bradford Cannon, such as the body’s ability to regulate pH, temperature, fluid volume, pressure, and osmolarity. These are recognized through highly evolved feedback systems, which act to finely tune many different chemical and electrical responses. For example:
* The concentration of ions in relations to one another (e.g. Na+, K+, H+) determine the body’s pH, which is closely regulated by the respiratory and urinary systems.
* Temperature in the body is determined by both the external environment of the organism as well as the amount of heat produced by catabolic reactions within the body regulated by respiratory and cardiovascular systems.
* Fluid volume and pressure, and osmolarity are regulated by the urinary, cardiovascular, and respiratory systems.
Physiology, then is the study of these systems’ integrated functions and the processes by which they maintain the milieu interieur, (internal environment), and thus our bodies health and well being.