Pouches of the large intestine that allow expansion and elongation are known as what?

• A. Haustra
• B. Villi
• C. Plicae
• D. Rugae

Answer: (A)

Haustra are the pouch-like segments of the large intestine that form as the circular muscle is gathered into bands called teniae coli. These sacculations give the colon its characteristic segmented appearance and, more importantly, allow it to expand and elongate as it fills with contents. The haustral pattern enables gradual mixing and propulsion of material along the colon, accommodating variability in stool volume without requiring a dramatic increase in length all at once.

Villi are tiny finger-like projections found in the small intestine that increase surface area for absorption, so they aren’t involved in the large intestine’s ability to expand. Plicae are circular folds in the mucosa of the small intestine that also boost absorption and surface area, not a feature of the colon. Rugae are folds in the stomach mucosa (and can accommodate gastric expansion) but are not the structures that create the large intestine’s expandable sacculations.