The Vascular Architecture of the Different Forms of Small Intestinal Villi in the Rat (Rattus norvegicus)

The vascular anatomy of the intestinal villi in the rat was studied by injection with Indian ink and silicone rubber. The vascular pattern in finger- leaf- and tongue-shaped villi is the same. One central arteriole divides into two marginal vessels, giving rise to a capillary net, which in turn collects into two para-axial venues. In ridge-shaped villi there are multiple arterioles and venules. It appears that finger-shaped villi turn into leaf-shaped villi by lateral upgrowth of the lamina propria, and that ridge-shaped villi are also formed by upgrowth of the lamina propria between adjacent leaf-shaped villi.