Human Anatomy and Physiology - N. I. Fedyukovich 2003

Metabolism and Energy Exchange

Various Forms of life are invariably and intrinsically linked to energy transformation. METABOLISM/26.html">Energy Metabolism is a defining characteristic of every living Cell. Energy-rich substances are assimilated by Cells, while metabolic end-products with a lower energy content are excreted. According to the first law of Thermodynamics, energy is neither created nor destroyed. A living Organism must acquire energy from its environment in an accessible form and return an equivalent amount of energy to the environment in a form less suitable for further use.

It is well established that a living organism and its environment form a unified system characterized by a continuous exchange of energy and matter. The normal physiological activity of an organism is sustained by The regulation of its internal components, which requires Energy Expenditure. The utilization of chemical energy within an organism is referred to as energy metabolism. This process serves as a primary indicator of the organism's overall condition and physiological activity.

Metabolic processes in which specific bodily components are synthesized from nutrients are termed anabolism (assimilation), whereas metabolic processes involving The breakdown of structural elements or the Processing of nutrients are termed Catabolism (dissimilation).