In the villus of the small intestine, where does cell division primarily occur?

• A. At the base of the crypts
• B. On the surface epithelium only
• C. At the tip of the villus
• D. Throughout the entire villus

Answer: (A)

Verified step by step guidance

1. Understand the structure of the villus in the small intestine: The villus is a finger-like projection that increases the surface area for absorption. It consists of epithelial cells, connective tissue, and blood vessels. At the base of the villus are crypts of Lieberkühn, which are invaginations containing stem cells.
2. Learn the role of the crypts of Lieberkühn: These crypts are responsible for housing stem cells that divide and differentiate into various types of epithelial cells. These cells migrate upward to replace old or damaged cells on the surface of the villus.
3. Recognize the location of cell division: Cell division primarily occurs at the base of the crypts of Lieberkühn, where stem cells are actively dividing. This ensures a continuous supply of new cells for the villus epithelium.
4. Eliminate incorrect options: The surface epithelium and the tip of the villus are composed of mature cells that do not divide. Cell division does not occur throughout the entire villus, as it is localized to the crypts.
5. Conclude that the correct answer is 'At the base of the crypts,' as this is the region where stem cells divide to maintain the integrity of the villus epithelium.