Capillary embryonic development new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a "de novo" production of endothelial cells which then form vascular tubes. The term angiogenesis denotes the formation of new capillaries from pre-existing blood vessels and already present endothelium which divides. Blood flows from the heart through arteries, which branch and narrow into arterioles, and then branch further into capillaries where nutrients and wastes are exchanged. The capillaries then join and widen to become venules, which in turn widen and converge to become veins, which then return blood back to the heart through
Inferior phrenic arteries Inferior phrenic arteries The inferior phrenic arteries are two small vessels, which supply the diaphragm but present much variety in their origin. They may arise separately from the front of the aorta, immediately above the celiac artery, or by a common trunk, which may spring either from the aorta or from the celiac artery. Sometimes one is derived from the aorta, and the other from one of the renal arteries; they rarely arise as separate vessels from the aorta. They diverge from one another across the crura of the diaphragm, and then run obliquely upward and lateralward upon its under