Fig. 1

Scheme of the conventional cellular composition of the lymphatic vascular system. Initial lymphatics (In) are composed of LECs (yellow) with microvalves that allow influx of interstitial fluid (curved arrows). Precollectors (P) have a mixed phenotype of both initial lymphatics and collectors (Col). The latter possess a continuous basement membrane underneath the LECs. Their wall is made up of dark and light smooth muscle cells (red), fibrocytes (green), interstitial Cajal-like pacemaker cells (blue), and mast cells (violet). The vegetative innervation of collectors and the vasa vasorum of the particularly muscular collectors are not shown. Straight blue arrows indicate the direction of lymph flow regulated by intraluminal valves