title: Changes in weightlessness in calcium metabolism and in the musculoskeletal system.
mesh_terms: D002118:Calcium / Q000378:metabolism*; D006801:Humans; D009132:Muscles / Q000378:metabolism; D009142:Musculoskeletal Physiological Phenomena; D009584:Nitrogen / Q000378:metabolism; D013026:Space Flight; D014893:Weightlessness
chemical_list: D009584:Nitrogen; D002118:Calcium