Figure 1.

Structure of intestinal villus with associated vasculature and lymphatic vessels. The vascular endothelium loops around from arteries to veins and back to the heart. It contains endothelial cells tightly packed against each other, with an outer layer of smooth muscle cells to facilitate blood flow. Lymphatic vessels are composed of lymphatic endothelial cells (LECs), which are loosely packed to facilitate the exchange of lymph, which is then moved through the vessels by a system of valves. They are connected through “button-like” junctions and are anchored to the extracellular matrix (ECM) by anchoring filaments.