Sha Wang, Ph.D., Postdoctoral Fellow (Gumucio Laboratory), Department of Cell and Developmental Biology, University of Michigan Medical School

To absorb nutrients from the food we eat every day, the inner wall of our intestine is lined with a massive number of tiny, finger-like projections called villi. Each villus acts as an absorptive unit; the cells lining the villus absorb the food, break it down, and then secrete nutrients from the base of the cell, into the core of the villus (bright pink dense areas), where these essential food products can enter the bloodstream for distribution to other organs, such as the liver. The convoluted surface of the villi helps to increase the total amount of surface area for absorption; it has been estimated that the effective absorptive surface area of the small intestine is about the size of half of a badminton court! In this section of the mouse fetal small intestine just before birth, the beautiful garden of villi is displayed. The green cells at the base of the villi are proliferating to continuously renew the absorptive surface.

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