stomach

abdomen ache anatomical anatomy animals appendix background bile biology blue body care cecum chewing colon cross digestion digestive dilated duodenum echinoderms esophageal esophagus following food functions gastric gut health healthy hollow human ileocecal ileum illustration important including insects inside internal intestine involved liver male mastication medical medicine mid molluscs muscular organ pain pancreas part phase pyloric rectum science second section some sphincter stomach stomache system tract ulcer valve vertebrates which white