ABSTRACT
The foregoing chapters have identified some of the many physical and chemical structures and strategies that participate in the human biological adaptations that determine health or disease. They perform in interactive, dynamic systems of increasing levels of complexity. The most fundamental level of integration is concerned with survival and growth of tissue cells and communication among them. The next level is populated by circulating chemical agents that communicate among cells at a distance and thereby evoke specific thermodynamic behaviors such as oxidative phosphorylation, bone building and repair, and metabolism of nutrients. At a higher level of integration are the interactions of various regulatory minisystems including cellular (cytokines), glandular, (hormones, enzymes, ligands, and their receptors), and partially independent neuronal plexuses such as those that direct simple adaptive functions in the heart and gut. 1
