GI Intro Flashcards
Name the blood supply of the foregut
celiac artery
includes liver, biliary tree, pancreas, stomach to mid third duodenum
Name the blood supply of the midgut
superior mesenteric artery
includes jejunum, ilium, appendix, to distal transverse colon
Name the blood supply of the hindgut
inferior mesenteric artery
includes distal transverse colon to rectum
Describe the two major branches of the celiac artery
The gastroduodenal artery passes immediately behind the duodenal bulb. Posterior bulb ulcers can cause life-threatening bleeding because of this.
The proper hepatic artery is small, and the liver receives the majority of its blood supply through the portal venous system through the hepatic portal vein.
Describe complications of blockage of the superior mesenteric artery
The SMA is the largest and supplies all the small intestine and half the colon. Acute blockage (thrombus, embolus) here leads to loss of the entire small bowel. Atherosclerotic changes in the SMA can lead to pain with eating and cause
patients to starve because of fear of that pain (sitophobia).
Describe complications of blockage of the inferior mesenteric artery
The inferior mesenteric artery is the smallest of the three and supplies only the lower colon and part of the rectum. It is most susceptible to ‘low flow states’ and can cause ischemic colitis from hypotension due to a cardiac arrest or severe systemic illness.
Describe autonomic innervation of the GI tract
The vagus nerve has the largest role on the parasympathetic side with additional input from the sacral nerves. They increase the activity of the gut.
Sympathetic innervation is from the dorsal root ganglia of the spinal nerves. In general the sympathetics inhibit gut activity and increase sphincter tone.
Peyer’s patches are found in the ____ and _____
jejunuma nd ileum
List the eight valves of the GI tract
Mouth Glossopharyngeal sphincter Upper esophageal sphincter Lower esophageal sphincter Pylorus Ampulla of vater Ileocecal valve Anal sphincter
