Physiologists may also specialize in determining how animals adapt to environmental stresses or how function develops along with the structure of developing, fertilized eggs. Of course other physiologists specialize in a particular system as respiration or the most popular, neurophysiology. Central Themes in Physiology. Function is based on structure. This is true at the molecular level as well as cellular, organ and organ system level.
Enzymes can be extremely specific about the function they carry-out.
Our digestive enzyme, amylase, will only separate glucose sugars that are joined in an alpha linkage. Other starches that we eat can cause problems because they are indigestible for us as some of the starches in beans. Genetics determines the proteins and enzymes that our cells will have. It also determines the limits of our function. One may wonder why the human kidney is not as efficient as that of a mouse, or why our lungs are nowhere as efficient as those of a bird.