Physiology is the
study of function and the mechanism of function of the various components
of plants and animals. Physiological questions are asked of tissues at
every level of structural complexity, ranging from questions of human behavior
(how does a conscious human control the position of his joints?), to questions
of the physics of ionic movement (how does an ion cross a membrane 3 nm
thick?). Physiological questions have a unity because the evolutionary
process which built biological structures is the same, whether the structures
are enzymes or ankles. Physiological questions have a unity because the
methods of describing and analyzing function are not diverse, even if the
structures performing those functions are. For example, the mathematics
describing the flow of current across membranes is intimately related to
the mathematics describing the control system for movement: a linear differential
equation is a linear differential equation, no matter what the meaning
of its coefficients. The unity of physiology arises then from the questions
it asks of biological systems and the unity of the mechanism that created
those systems. The diversity of physiology arises from the range of systems
about which those questions are asked. The excitement of physiology arises
from the tension between its unity and diversity. When new systems arise,
old questions are asked of them, at first. When new questions or methods
arise in the new system, they are then applied to old problems. And applied
to old problems, the new questions are often as revealing as when applied
to the new systems, where they arose. Whether the unity of physiology is
a reflection purely of reality (that is of the unity of biology), or a
reflection of the paucity of our knowledge, or even a reflection of the
inherent limitations of our nervous system, is not known. Probably all
three.
Molecular Biophysics & Physiology Home | Rush University | Medical Center