 Gastrointestinal System Anatomy In this learning activity, you will review the parts of the gastrointestinal system. The abdomen is divided into four quadrants. Quadrant 1, quadrant 2, quadrant 3, and quadrant 4. Let's look at each term and see that part of the abdomen highlighted in red. Liver, gallbladder, common bile duct, duodenum, ascending colon, cecum, stomach, pancreas, descending colon, sigmoid colon, rectum, appendix, transverse colon. This completes the activity Gastrointestinal System Anatomy.