Final answer:
The celiac artery, also known as the celiac trunk, is the largest branch of the abdominal aorta that supplies oxygenated blood to the upper digestive tract.
Step-by-step explanation:
The largest branch of the abdominal aorta, which supplies oxygenated blood to the upper digestive tract, is the celiac artery. It is also known as the celiac trunk, which is a major branch of the abdominal aorta giving rise to the left gastric artery, the splenic artery, and the common hepatic artery. These arteries in turn supply blood to the stomach, spleen, liver, duodenum, and gall bladder, amongst other upper digestive tract organs. On the other hand, the superior mesenteric artery supplies blood to the small intestine, pancreas, and a majority of the large intestine, whereas the inferior mesenteric artery supplies the distal part of the large intestine.