According to the World Health Organization (WHO), cardiovascular disease (CVD) is the number one cause of death. Approximately 20 million people die of CVD each year. The cardiovascular system is a branched network of cellular tubes connected to a central pump, the heart. It works in tandem with the lymphatic system, which drains tissues of fluid and debris from metabolism to maintain tissue health. We investigate the small blood vessels of the cardiovascular system molecularly and cellularly to find out how they emerge and interact with tissues, so they can optimally function within the entire organism.