Final answer:
The thoracic duct is responsible for draining the intestinal tract of the abdominal cavity. It does so by collecting lymph from the lower abdomen via the intestinal trunk and channeling it into the left subclavian vein.
Step-by-step explanation:
The thoracic duct drains the intestinal tract of the abdominal cavity. It is part of the lymphatic system, originating beneath the diaphragm in the cisterna chyli. The thoracic duct receives lymph from the lower abdomen, pelvis, and lower limbs through the left and right lumbar trunks and the intestinal trunk. The lymphatic fluid carrying digested fats and immune cells then moves up the thoracic duct, eventually draining into the left subclavian vein.
Abdominal Aorta and Major Branches
While the thoracic duct is crucial for lymph drainage, the abdominal cavity's blood supply is provided by the abdominal aorta after passing through the diaphragm. This major artery gives rise to the celiac trunk, superior mesenteric artery, and inferior mesenteric artery. The superior mesenteric artery supplies blood to parts of the small and large intestines, while the inferior mesenteric artery supplies the distal segment of the large intestine.