Ischemia: (1) strangulation: severe pain, surgical emergency cause it can progress to infarct, caused by volvulus, incacerated hernia, etc; (2) mesenteric ischemia and infarct due to embolism, thrombosis, rupture or compression; risk factors e.g. atrial fibrillation; chronic gut claudication causes post-prandial pain, weight loss, nausea, vomiting and diarrhea