The Stomach:
Anatomy of the stomach:
The stomach lies just below the diaphragm in the upper part of the abdominal cavity primarily to the left of the midline under a portion of the liver. Anatomically, the stomach can be divided into three major regions: the fundus (the most proximal), the corpus and the antrum. The stomach is suspended from the abdominal wall by the lesser omentum. The greater omentum attaches the stomach to the transverse colon, spleen and diaphragm. The common mesentery suspends the small intestine. The parietal peritoneum lies over the duodenum and other structures, such as the abdominal aorta. Because they lie behind the peritoneum, they are called retroperitoneal structures.
The primary divisions of the stomach include:
Cardia:
The cardia is the portion of the stomach that surrounds the cardioesophageal junction, or cardiac orifice (the opening of the esophagus into the stomach).Fundus:
The fundus is the enlarged portion to the left and above the cardiac orifice.Body:
The body (also known as the corpus) is the central part of the stomach.Pyloric antrum:
The pyloric antrum is the lower (distal) portion above the duodenum. The opening between the stomach and the small intestine is the pylorus, and the very powerful sphincter which regulates the passage of chyme into the duodenum is called the pyloric sphincter.
Functions of the stomach:
The primary functions of the stomach are storage and digestion of food. Storage of food is important because while a person eats its food over a short period of time, digestion takes much longer. The stomach also empties the partially digested food in small amounts into the small intestines. Other important secondary functions of the stomach include the secretions of a hormone called gastrin as well as intrinsic factor. Gastrin stimulates acid secretion by the stomach. Secretion of an "intrinsic factor" is important for absorption of vitamin B12, which is important for the development and formation of red blood cells.
The stomach helps with the mechanical breakup of food. Waves of contraction in the muscular middle layer of the stomach churn the food, breaking it up as well as mixing it with gastric juices. The stomach also aids in the enzymatic digestion of food. Some of the inner layers' glands secrete a mucous lining for the stomach, protecting it from the gastric juices, a mixture of hydrochloric acid and digestive enzymes that are secreted by the other set of stomach-lining glands. The highly acidic mixture of food and gastric juices leaves the stomach for the small intestine through the pyloric sphincter.
Common disorders of the stomach:
| University of Missouri Health Care | This information is not intended to replace the advice of a doctor. |
