The vascular architecture of the small intestinal mucosa of the monkey (Macaca mulatta)

Silicone rubber microvascular injection compounds have been used to describe the mucosal vascular architecture of the monkey's small intestine. The mucosal vascular patterns of this animal differ from the classical description. Instead of the villus blood supply being delivered via a central villus arteriole, the arterioles ramify to the undersurface of the mucosa where they terminate in the capillary plexus surrounding the crypts of Lieberkuhn. The villus capillary net is derived directly from the cryptic capillary plexus and is drained by a single, central villus vein. There is a secondary venous return system that directly drains the cryptic plexus. These secondary venous channels might represent a mechanism that regulates the proportional distribution of blood in the cryptic and villus capillary beds. This report is intended to describe the vascular patterns only as they occur in the monkey. Observations of rat and rabbit mucosa prepared by the same technique reveal arterial and venous channels extending the length of the villi. These animals, therefore, more closely resemble the classical description.