Metabolism

Metabolism is the sum of all the chemical and physical processes that occur within the body. It includes the repair and replacement of dead or damaged tissues and the production of energy. Metabolism involves two basic processes: anabolism and catabolism. Anabolism is the synthesis of complex substances from simpler ones, which occurs during the growth of body tissues. Catabolism is the reverse process, the breakdown of complex substances into simpler substances. The "basal metabolic rate" (BMR) is a measure, expressed in calories, of the body's energy expenditure when at complete rest.