The muscularis of the stomach is composed of how many smooth muscle layers?

• A. Two
• B. Four
• C. One
• D. Three

Answer: (D)

Verified step by step guidance

1. Understand the structure of the stomach wall, which consists of four main layers: mucosa, submucosa, muscularis, and serosa. The muscularis layer is responsible for the stomach's movements and churning of food.
2. Recall that the muscularis layer in most parts of the gastrointestinal tract typically has two layers of smooth muscle: an inner circular layer and an outer longitudinal layer.
3. Recognize that the stomach is unique because its muscularis layer has an additional layer of smooth muscle. This third layer is the innermost oblique layer, which enhances the stomach's ability to mix and churn food.
4. Visualize the arrangement of the three smooth muscle layers in the stomach: the innermost oblique layer, the middle circular layer, and the outer longitudinal layer. These layers work together to perform mechanical digestion.
5. Conclude that the muscularis of the stomach is composed of three smooth muscle layers, which is a distinguishing feature compared to other parts of the gastrointestinal tract.