blood vessel endothelial cell endothelial tip cell ZFA:0009303 Endothelial tip cells are a specialized type of cell that play a crucial role in angiogenesis, the formation of new blood vessels from the existing vasculature. These cells are located at the ends of growing capillary sprouts, their position giving them the term "tip" cells. Endothelial tip cells are characterized by a number of attributes which facilitate them to lead the way in angiogenesis: They have a highly dynamic, large, and polarized shape, and they extend numerous long and mobile filopodia, or finger-like projections, which continuously probe the extracellular microenvironment for cues that control the growth and movement of the cells. The filopodia are equipped with several receptors, including Vascular Endothelial Growth Factor Receptor (VEGFR) -2 and -3, which respond to guidance signals during angiogenesis. Their distinctive morphology with a broad leading edge and small cell body trailing behind helps in efficiently moving in the right direction responding to cues. The function of endothelial tip cells is fundamental to the angiogenesis process. Guiding the sprouting vessel, they direct the subsequent proliferation and migration of the stalk cells, which follow the tip cells and form the body of the sprout. These tip cells do not proliferate, but instead, dictate the division of stalk cells, leading to the elongation of the sprout. They also help in lumen formation. The guidance and sprouting decisions of endothelial tip cells are critical for creating a functional and efficient network of vessels that can appropriately supply oxygen and nutrients to tissues. Notably, tip cells play a role in pathological conditions such as tumor angiogenesis and eye diseases, making them an important area of research in cell biology and medicine. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) https://cellxgene.cziscience.com/cellguide/CL_0000704 A specialized endothelial cell that senses extracellular signals and guides the directed growth of blood vessels.