Which anatomical feature of the stomach allows it to expand as it fills?

• A. Plicae Circulares
• B. Microvilli
• C. Villi
• D. Rugae

Answer: (D)

The stomach expands mainly because of gastric rugae. These are folds of the mucosa and submucosa that line the stomach. When the stomach is empty, the rugae are prominent, but as it fills, they unfold and flatten, letting the organ stretch to accommodate a larger volume without a big rise in pressure. This folding-and-flattening design is what lets the stomach hold meals of varying sizes.

Plicae circulares are folds found in the small intestine that increase surface area and slow movement of contents, not used for stretching the stomach. Microvilli and villi are tiny projections on the surface of enterocytes in the small intestine that maximize nutrient absorption, not involved in stomach distension.