Answer:
Step-by-step explanation:
The correct order of the steps of angiogenesis is:
Stimulation of endothelial cells by VEGF
Endothelial cell extension of filopodia
Formation of capillary sprout
Pinocytic vesicles fusing to form large vesicles
Creation of a lumen that runs through capillary sprout
Angiogenesis is the process of creating new blood vessels from existing ones. It is a regulated process that occurs in response to various stimuli, such as tissue hypoxia or inflammation. The first step in angiogenesis is the stimulation of endothelial cells by vascular endothelial growth factor (VEGF). This protein promotes the proliferation and migration of endothelial cells, which are the cells that line the inner surface of blood vessels.
Next, the stimulated endothelial cells extend filopodia, which are thin, hair-like protrusions that help them to explore and migrate through the surrounding tissue. As the filopodia grow and interact with the extracellular matrix, they form a capillary sprout, which is a small, tubular structure that begins to take shape.
During this process, pinocytic vesicles, which are small, membrane-bound vesicles that are involved in the uptake of extracellular fluid and substances, fuse to form large vesicles. These vesicles help to provide the necessary nutrients and support for the developing capillary sprout.
Finally, the capillary sprout continues to grow and differentiate, eventually forming a lumen, or a central cavity, that runs through the center of the sprout. This allows blood to flow through the newly formed blood vessel.