Which portion of the small intestine is capable of compensation and adaptation after ileal resections?

• A. The ileum
• B. The jejunum
• C. The colon
• D. The stomach

Answer: (A)

The ileum is capable of compensation and adaptation after ileal resections. When part of the ileum is removed, the remaining ileal tissue undergoes structural and functional changes to maximize absorption. This includes mucosal adaptation such as villus hypertrophy and deeper crypts, increasing the absorptive surface, and upregulation of transport mechanisms to reclaim bile acids and vitamin B12 to a greater extent. While other segments of the small intestine can show some adaptive changes, they cannot fully replace ileal functions, and the colon or stomach are not the primary sites for compensating ileal loss.