What is the Anatomy of the Stomach?
The stomach is a J-shaped muscular sac between the esophagus and the small intestine, where food is mixed with gastric juice and partially digested. It has distinct regions, two curvatures, and two orifices that control the entry and exit of food.
The stomach is divided into the cardia, fundus, body, and pyloric part (antrum and pylorus), bordered by the lesser curvature (right, concave) and greater curvature (left, convex), with the pyloric sphincter controlling emptying into the duodenum.
- 1↓CardiaReceives food from the esophagus at the cardiac orifice; contains the gastroesophageal junction.
- 2↓FundusDome-shaped region above the cardia, stores swallowed air and gas.
- 3↓BodyThe largest region; main site of gastric acid and enzyme secretion.
- 4↓AntrumGrinds food into chyme and mixes it before pushing it toward the pylorus.
- 5PylorusNarrow outlet with the pyloric sphincter, releases chyme into the duodenum in controlled spurts.
Step-by-step worked examples
A radiologist sees contrast pooling in the most superior, dome-shaped part of the stomach on an upright X-ray. Which region is this?
The stomach's regions from top to bottom are cardia, fundus, body, antrum, and pylorus. The fundus is the dome-shaped region located above and to the left of the cardia, where swallowed gas collects when upright. Answer: the fundus.
During surgery, the surgeon identifies the concave, shorter border of the stomach on its right/superior side. What is this border called?
The stomach has two curvatures: the lesser curvature (short, concave, right side) and the greater curvature (long, convex, left side). The shorter, concave border described is on the right/superior side. Answer: the lesser curvature.
A gastric emptying study shows chyme passing through a narrow, muscular ring into the duodenum. Which structure controls this?
The pyloric part of the stomach ends in the pylorus, guarded by the pyloric sphincter. This sphincter regulates the rate at which chyme leaves the stomach and enters the duodenum. Answer: the pyloric sphincter.
Flashcards
Quick quiz
Q1.Which stomach region is directly continuous with the esophagus?
Q2.Which curvature is long and convex?
Q3.What structure controls chyme release into the duodenum?
Q4.Which region grinds and mixes food before it reaches the pylorus?
The full card deck, worked steps and AI-tutor support for “What is the Anatomy of the Stomach?” are in Notek — study by hand before your exam.
Common mistakes
The fundus is the lowest part of the stomach. — Correct: The fundus is the dome-shaped region above the cardia, not the lowest part — the pylorus is the most distal region functionally.
The greater curvature is shorter than the lesser curvature. — Correct: It's the opposite: the greater curvature is the longer, convex border; the lesser curvature is shorter and concave.
The pyloric sphincter controls entry of food from the esophagus. — Correct: The pyloric sphincter controls exit of chyme into the duodenum; the cardiac orifice/LES governs entry.
The stomach digests food completely before it reaches the small intestine. — Correct: The stomach only partially digests food into chyme; most digestion and absorption happen in the small intestine.
FAQ
What are the parts of the stomach?
The stomach is divided into the cardia, fundus, body, and pyloric part (antrum and pylorus).
What is the difference between the lesser and greater curvature?
The lesser curvature is the short, concave right border; the greater curvature is the long, convex left border.
What does the pylorus do?
The pylorus is the stomach's outlet; its pyloric sphincter releases chyme into the duodenum in controlled amounts.
Where does food enter and exit the stomach?
Food enters at the cardiac orifice (from the esophagus) and exits at the pyloric orifice (into the duodenum).