abdomen anus appendix blind gut bowels brain cecum census colon composition constituents content contents divisions duodenum elements endocardium entrails foregut giblets gizzard guts heart hindgut index ingredients innards inner mechanism internals intestine inventory inwards items jejunum kidney kishkes large intestine list liver liver and lights lung midgut part parts perineum pump pylorus rectum small intestine spleen stomach ticker tripes vermiform appendix viscera vitals whole works