Digestive tract and accessory organs
The digestive system combines passageways with organs that help process food. Review the arrangement of these structures and their relationships with the peritoneum.
212 explained questions · practice, exam and sprint · freeThe mouth, pharynx, esophagus, stomach, small intestine and large intestine form a continuous tract. The liver, gallbladder and pancreas contribute secretions, but food does not pass through their parenchyma. The liver produces bile, the gallbladder stores and concentrates it, and ducts deliver it to the duodenum. Exocrine pancreas supplies enzymes and bicarbonate. Production, storage and transport are separate functions.
The digestive wall generally includes mucosa, submucosa, muscularis externa and an outer serosa or adventitia, depending on anatomical relationships. Mucosa contains epithelium, lamina propria and muscularis mucosae. The stomach specializes in mixing and secretion. Small-intestinal folds, villi and microvilli increase absorptive area. A microvillus is a cellular projection, whereas a villus contains epithelium and a connective-tissue core.
The small intestine proceeds through duodenum, jejunum and ileum. The duodenum receives biliary and pancreatic secretions, while jejunum and ileum continue absorption with regional specializations. The ileum joins the cecum. The large intestine continues through ascending, transverse, descending and sigmoid colon, rectum and anal canal. Colonic water and electrolyte absorption is important, but substantial water absorption also occurs in the small intestine.
Section references: [2]
Parietal peritoneum lines the wall; visceral peritoneum covers organ surfaces. Mesenteries support segments and carry vessels, nerves and lymphatics. Intraperitoneal does not mean an organ floats within cavity fluid. Much of the duodenum and pancreas is secondarily retroperitoneal, with the pancreatic tail an important exception. Portal venous blood from much of the gut reaches the liver before systemic circulation; lymph follows a different route.
| Structure or concept | Distinguishing feature |
|---|---|
| Liver | Produces bile; receives portal and arterial blood. |
| Gallbladder | Stores and concentrates bile. |
| Villus | Mucosal projection with a connective core. |
| Microvillus | Apical projection of an individual cell. |
Try answering before opening the explanation. Each example develops a point from the guide.
Answer: Duodenum → jejunum → ileum
The small intestine begins at duodenum, continues through jejunum and ends at ileum, which joins the cecum. Distinguish this sequence from the colon and from ducts entering the duodenum.
Why the other options do not fit: The other alternatives reverse parts of the route. Bile and pancreatic secretion enter the duodenum, but their ducts are not small-intestinal segments.
Answer: Stomach
The stomach receives the esophagus at the cardia and continues through the pylorus toward the duodenum. It is a digestive-tract dilation involved in storage, mixing and secretion.
Why the other options do not fit: Liver and pancreas are accessory organs whose parenchyma does not transmit food. Transverse colon is part of the large intestine, downstream from the small intestine.
Answer: Liver
Bile is produced in the liver. The gallbladder stores and concentrates it, and ducts deliver it toward the duodenum. Production and storage are distinct stages.
Why the other options do not fit: Gallbladder is not the primary production site. Pancreas supplies pancreatic secretions and duodenum receives bile; neither replaces the liver as the bile-producing organ.
If a relationship is missing, return to the relevant section. Then practice a short set and save persistent uncertainties in your review notebook.
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