organs of gastrointestinal tract: stomach, liver, gallbladder and pancreas. concept photo of anatomical structure of the upper par

activity alimentary anatomical anatomy background bile biliary bilious bubble canal cancer concept digestive disease disorder duodenum enzyme figure form function gallbladder gastric gastrointestinal gut health hormone human liver major medical medicine metabolism model normal organs pancreas part pathology photo set shape stomach structure study symptom system tract upper white work