The IMA is ligated (occluded) when removing an aneurysm of theabdominal aorta. The IMA normally supplies arterial blood to thesigmoid colon and rectum. Uusualy, the sigmoid colon and rectumsurvive such a ligation. How do they survive? discuss the normalblood supply to the entire GI tract (in chart/table form,with names of arteries and names of corresponding structures), andthen what occurs after the IMA is ligated to keep the sigmoid colonand rectum alive.
