The stomach is a vital organ in the digestive system, and understanding its gross anatomy is essential for grasping how it functions. The stomach can be divided into several key regions, each with distinct roles in the digestive process. The first region is the cardia, located at the upper portion near the junction with the esophagus. The bolus of food passes through the cardiac sphincter into the cardia, which is situated close to the heart.
Next is the fundus, which bulges upwards from the cardia and can be thought of as the roof of the stomach. This region is important for the storage of undigested food and gases released during digestion. The main section of the stomach is referred to as the body or corpus, which has a J-shaped curve and is responsible for the majority of the stomach's digestive activities.
At the lower end of the stomach lies the pyloric part, which acts as a gatekeeper to the small intestine. This region can be further divided into three sections: the pyloric antrum, the pyloric canal, and the pyloric sphincter. The pyloric antrum serves as the entry point to the pyloric part, while the pyloric canal narrows as it approaches the sphincter. The pyloric sphincter is a muscular valve that regulates the passage of chyme into the duodenum, the first section of the small intestine.
To aid in memorization, one might use a mnemonic: "My car is fun, but the body is a pile of junk," which corresponds to the cardia, fundus, body (corpus), and pyloric part. Additionally, the inner surface of the stomach features rugae, which are folds that allow the stomach to expand when filled with food. These folds create a wrinkly appearance when the stomach is empty.
Finally, the stomach has two important curvatures: the lesser curvature, which is the smaller, sharper curve on the inner side, and the greater curvature, which is the larger curve on the outer side. Understanding these anatomical features is crucial for comprehending the stomach's role in digestion and its interaction with other digestive organs.