What is the main role of the rectum?

• A. Absorption of nutrients
• B. Storage of feces
• C. Gas exchange
• D. Regulation of breathing

Answer: (B)

The rectum’s main job is to store feces until you’re ready to defecate. After most water has been absorbed earlier in the large intestine, stool passes into the rectum where stretch receptors signal fullness and trigger the defecation urge. It then works with the anal sphincters to control release at an appropriate time. This role is different from nutrient absorption, which happens mainly in the small intestine (and earlier parts of the large intestine for some water reabsorption), gas exchange, which occurs in the lungs, and breathing regulation, which is controlled by the respiratory system.