Metabolic systems with re-cycling.
D000293:Adolescent; D000328:Adult; D002648:Child; D004912:Erythrocytes / Q000378:metabolism*; D004920:Erythropoiesis; D006461:Hemolysis; D006801:Humans; D008962:Models, Theoretical; D011868:Radioisotopes
D011868:Radioisotopes