FIGURE 1.

Morphology and structure of afferent lymphatics. Afferent lymphatics begin as blind‐ended capillaries present in peripheral tissues. Capillaries are composed of oakleaf‐shaped LECs that are connected by discontinuous button‐like cell‐cell junctions. These junctions create open flaps between neighboring LECs that facilitate leukocyte entry and uptake of fluids and macromolecules. LECs also possess anchoring filaments that connect to the ECM and regulate the opening of the flaps. Capillaries are further surrounded by a thin and fenestrated BM. Lymphatic capillaries subsequently merge into collecting vessels. In contrast to the capillaries, LECs in collecting vessels are elongated and tightly connected to each other by zipper‐like cell‐cell junctions. Collectors are surrounded by a thick BM as well as LMCs. Collectors further have valves, which upon vessel contraction support unidirectional fluid flow toward the dLN