The majority of the digestive tract is composed of two muscular layers to allow for peristalsis — that is, the movement of food. The stomach, however, is composed of three layers, and is designed to account for mechanical digestion. Let’s use Complete Anatomy to identify each layer in 3D, and learn its function.
- The outer longitudinal layer is involved in peristalsis.
- The middle, circular layer contributes to the pyloric sphincter, and helps control movement of food to the duodenum.
- Finally, the inner oblique layer is unique to the stomach. It tapers off before the duodenum, and is important for the churning of food and digestion.
In summary: the outer longitudinal and the middle circular layer continue into the duodenum, whereas the inner oblique layer tapers off before the pyloric sphincter.