<prompt> The small intestine is characterized by basal crypts and superficial villi Figure below. Where does cell division take place?Schematic representation of villi and crypts of LieberkuhnSubmucosaCryptsVilliSmall-bowel lumen  <response>: Small-bowel turnover can be measured in rats by autoradiographic studies in which turnover of cells located in the crypts migrate along the villus toward the tip over a 2- to 3- day period. Intestinal villous mucosa undergoes hypertrophy and hyperplasia whenever an increased food load continuously enters the small intestine. 