Alexis Carulli, Graduate Student (Samuelson Laboratory), Department of Molecular and Integrative Physiology, University of Michigan Medical School
This is a face view of the mouse small intestine, which has been cut open to reveal an inner epithelial lining that functions to absorb nutrients from food. The ruffled appearance of the surface is due to millions finger-like projections called villi that project from the surface, creating a surface area for absorption that is about the size of half of a tennis court. Since the villi are in constant contact with the external environment, its cells are constantly shed and need to be renewed. In fact, the entire surface shown here turns over every 4-5 days! Our laboratory studies the dynamic regulation of the intestinal stem cells that are responsible for the constant renewal of this cellular layer throughout life.