The digestive and excretory systems together function to process all nutrients that enter the bloodstream except the oxygen that is brought in by the respiratory system. Through the digestive system, nutritive substances are absorbed and any that are not are eliminated. The excretory system functions in parallel, eliminating the by-products of metabolism from the cells throughout the body, by its constant cleansing of the blood. Both systems, in addition to serving these life-support functions, also have associated with them numerous psychological meanings regarding the ingestion of food, and the elimination of wastes through the gastrointestinal system and the genitourinary tract.
KeywordsFatigue Starch Osteoporosis Creatinine Dementia
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