Blood Circulation in the Liver

This system serves the intestines, spleen, pancreas and gall bladder. The liver receives it blood from two main sources. The main sources are the hepatic artery, which as a branch of the aorta, supplies oxygenated blood to the liver and the hepatic portal vein, which is formed by the union of veins from the spleen, the stomach, pancreas, duodenum and the colon. The hepatic portal vein transports, inter alia, the following blood to the liver:
• absorbed nutrients from the duodenum;
• white blood cells (added to the circulation) from the spleen;
• poisomous substances, such as alcohol which are absorbed in the intestines, and
• waste products, such as carbon dioxide from the spleen, pancreas, stomach and duodenum.
The hepatic artery and hepatic portal vein open into the liver sinuses where the blood is in direct contact with the liver cells. The deoxygenated blood, which still retains some dissolved nutrients, eventually flows into the inferior vena cava via the hepatic veins.Coronary Circulation

While the liver serves a variety of functions, the most crucial is its role in the body's metabolism. There is no organ that is more important to healthy metabolism than the liver - in many ways, it is as central to metabolism as the heart is to the circulation of blood. The liver plays a critical role in four key areas of metabolism: fuel management, nitrogen excretion, the regulation water distribution between the blood and tissues, and the detoxification of foreign substances.
Because of the crucial importance of healthly metabolism to overall health, diseases of the liver, such as hepatitis C, can be devastating, leading to fatigue, malaise, and even to death.

CT images of the abdomen.

Branches of the Abdominal Aorta

Abdominal Aorta
The abdominal aorta is a region of the descending aorta, originating superiorly as a continuation of the thoracic aorta as it passes through an opening in the diaphragm, and terminating inferiorly as the abdominal aorta bifurcates (divides into two structures) into the left and right common iliac arteries.
The abdominal aorta is a large-lumened, unpaired arterial vessel that is part of the main trunk of the systemic arterial system. As such, the abdominal aorta supplies oxygenated blood, pumped by the left ventricle of the heart, to the abdominal and pelvic organs and structures via visceral and parietal arterial branches.
The abdominal aorta and its major arterial branches are highly elastic. During systole (heart muscle contraction), the aortic and arterial walls expand to accommodate the increased blood flow. Correspondingly, the vessels contract during diastole and elastin fibers assure that this contraction also serves to drive blood through the arterial vessels.
As the thoracic aorta passes through the aortic hiatus (an opening in the diaphragm) it becomes the abdominal aorta. The abdominal aorta ultimately branches into left and right common iliac arteries. The common iliac arteries then branch into internal and external iliac arteries to supply oxygenated blood to the organs and tissues of the lower abdomen, pelvis, and legs.
Major branches of the abdominal aorta include, ventrally, the celiac branches, and superior and inferior mesenteric arteries. On the dorsal side of the aorta are the lumbar and median sacral branch arteries. Lateral to the aorta are the inferior phrenics, middle supernal, renal, and ovarian or testicular arteries. Because the branches from the abdominal aorta are large, the aorta rapidly decreases in size as it courses downward (inferiorly) through the abdomen.
The celiac trunk divides into three major branches: the left gastric artery to the stomach, the hepatic artery to the lobes of the liver, and splenic artery--surrounded by a plexus of nerves--that ultimately terminates in branches entering the hilus of the spleen.
The superior mesenteric artery supplies oxygenated blood to the small intestine below the duodenum and portions of the cecum and colon. There is often a remnant of the umbilical artery, in the form of a fibrous strand that runs between the navel (umbilicus) and the superior mesenteric artery. Branches of the superior mesenteric artery include the inferior pancreaticoduodenal artery, jejunal and ileal branches, illeocolic artery and the right and middle colic arteries.
The inferior mesenteric arteries supply the transverse colon, descending colon, and rectum. Branches of the inferior mesenteric include the left colic artery, the sigmoid arteries (inferior left colic artery and the superior rectal artery).
Middle suprarenal arteries branch from the abdominal aorta to supply the suprarenal glands. Renal arteries branch form the abdominal aorta to supply the kidneys. Phrenic branches of the abdominal aorta supply oxygenated blood to the diaphragm.
As a region of the descending aorta, the abdominal aorta arises in the embryo from the dorsal aortas that are located on each side of the notochord. At about the end of the first month of development these embryonic dorsal aorta fuse to form the descending aorta. In the embryo, there are three important divisions of arteries branching from the abdominal aorta. A splanchnic group of arteries supplies the Gastrointestinal tract. A urogenital group of arteries supplies organs and structures derived from the intermediate cell mass, including the kidneys, suprarenals, and gonads. A dorsal and lateral group of arteries supply arterial branches to the spinal cord, vertebrae, and muscles and skin of the dorsal body wall.