1. Unit 18 GI Tract and Vessels

2. Quiz

3. Patient Symptoms Fifty year old male, smoker, obese –Deep burning retrosternal pain –Reflux of gastric contents (heartburn) –Patient has to sit up to get a good night’s sleep –Patient responds temporarily to antacids

4. The Abdominal Aorta begins at the aortic hiatus of the diaphragm (T12) and divides into Common Iliac arteries at L4 Major branches to the GI tract are: Celiac Trunk - T12 Superior Mesenteric - L1 Inferior Mesenteric - L3 C S I

5. Celiac Trunk and Branches

6. After dissecting away the lesser omentum, clean and identify the branches of the Celiac Trunk: Left Gastric Common Hepatic Splenic You may have to reflect the upper border of the pancreas downward; watch for nerve plexuses Plate 300 Left Gastric Common Hepatic Splenic C Celiac Trunk Foregut derivatives are supplied by the celiac trunk

7. Expose the terminal branches of the Common Hepatic Artery: Gastroduodenal Hepatic Artery Proper Plate 300 Left Gastric Common Hepatic Splenic C Hepatic Artery Proper Gastroduodenal Artery

8. The Right Gastric Artery is usually a branch of the Hepatic Artery Proper Plate 300 Left Gastric Common Hepatic Splenic C Hepatic Artery Proper Gastroduodenal Artery Right Gastric Artery The Right and Left Gastric arteries form a strong anastomosis

9. The Right Gastroomental artery ( Gastroepiploic) is a branch of the Gastroduodenal Artery - it runs in the greater omentum Plate 300 Rt. Gastroomental Artery Gastroduodenal Artery Splenic Artery

10. Stomach up At the hilum of the spleen, identify the Splenic Artery and its branches: Left Gastroomental Artery Short Gastric Arteries Pancreatic Arteries Plate 291 (old) Short Gastric Arteries in the Gastrosplenic Ligament Splenic Artery running across the floor posterior to the omental bursa Left Gastroomental Artery Pancreatic Branches Also identify the Splenic Vein

11. Plate 300 Rt. Gastroomental Artery Gastroduodenal Artery Left Gastroomental Artery Splenic Artery *The right gastroomental artery has enough branches to take care of the whole stomach e.g., in an esophageal resection The Right and Left Gastroomental arteries form a strong anastomosis

12. Keep in mind that there are many variations in the arteries of this region!

13. Remove some of the peritoneum from the right side of the mesentery of the small intestine.

14. Superior Mesenteric Vessels

15. Notice how the Superior Mesenteric vessels pass between the Neck and Uncinate Process of the pancreas to enter the mesentery of the small bowel Plate 298 Body Uncinate Process Neck Tail Head Superior Mesenteric Vessels Attachment of mesentery of small intestine Superior Mesenteric Artery L1

16. Clean and identify some of the 18 or more Jejunal and Ileal branches of the Superior Mesenteric Artery and Vein Plate 306 Jejunal branches Ileal branches Superior Mesenteric Artery They ramify within the mesentery of the small intestine Supplies viscera derived embryologically from midgut

17. Jejunal branches Ileal branches Plate 306Superior Mesenteric Artery Now identify the following branches that come off the SMA to the right: Ileocolic Appendicular Right Colic Middle Colic Appendicular Artery Right Colic Artery Ileocolic Artery Middle Colic Artery Cut

18. Incise the anti-mesenteric border (free) of a portion of jejunum and ileum to study the mucosal lining. Also, look for differences in the branching patterns of the arteries.

19. Differences between jejunum and ileum include: jejunum is often empty; circular folds are more prominent; fewer arterial anastomotic loops in the mesentery; areas of fat-free mesentery near mesenteric border Plate 280AJejunum Anastomotic loop (arcades) Straight Arteries Circular Folds Fat-free window These differences are more apparent in the living person Barium Radiograph Jejunum means empty

20. Ileum: Lymphoid Nodules; fewer circular folds; more numerous, shorter and complex arterial anastomotic loops; no fat- free mesenteric border Plate 280B Ileum Anastomotic loops (arcades) Lymphoid Nodule Fat Circular Folds Shorter Straight Arteries Note also the complete inner circular and outer longitudinal muscle layers C L Barium Radiograph Ileum means rolled up or twisted

21. Gastric Folds or Rugae Plate 276Stomach Incise the stomach along its greater curvature and check out the gastric folds. Carry the incision down through the pyloric sphincter region into the first part of the duodenum, called the duodenal bulb or ampulla. Bulb/Ampulla

22. The duodenal bulb or ampulla is the area where 80% of peptic ulcers occur - 65% of ulcers in the duodenum are in the posterior wall. These ulcers are usually (90%) associated with the presence of Helicobacter pylori infection. Folks with severe chronic anxiety are most prone to the development of peptic ulcers (high acidity – 15X higher – leaves mucosa vulnerable to H. pylori). Bulb/Ampulla Plate 279 Moore, page 257 Treat with antacids and antibiotics

23. Ampulla Notice what artery is behind the posterior wall of the duodenal ampulla - can be eroded in a perforating peptic ulcer Plate 279 Gastroduodenal Artery Common Hepatic Artery Duodenum The Splenic Artery can also be eroded

24. An acute duodenal ulcer is seen in two views on upper endoscopy. D D

25. Pylorus

26. Radiograph of the pyloric region and duodenal ampulla following a barium meal Peristaltic wave

27. Inferior Mesenteric Vessels

28. Clean and identify the Inferior Mesenteric Artery and identify the following branches: Left Colic Sigmoid (4) Superior Rectal Supplies viscera derived embryologically from hindgut Plate 307 Sigmoid Arteries in sigmoid mesocolon Left Colic Superior Rectal Artery Inferior Mesenteric Artery L3

29. Identify the Marginal Artery and review the Middle Colic Artery Middle Colic in transverse mesocolon Marginal Artery (of Drummond) Plate 307Marginal Artery IMA The Marginal Artery represents an anastomosis between the SMA and IMA; if the aorta is blocked, this anastomosis as well as others will compensate

30. Plate 309 The Portal Vein collects blood from the GI tract and delivers it to the liver for metabolism of nutrients Portal Vein Splenic Vein Inf. Mesenteric Vein Sup. Mesenteric Vein Portal Vein IVC Pancreas Stomach Cut Identify the veins that make up the Portal Vein posterior to the neck of the pancreas: Superior Mesenteric Vein Splenic Vein Inferior Mesenteric Vein

31. Plate 290 To IVC Blood from GI tract Portal Vein Hepatic Vein Common Hepatic Duct Hepatic Artery Proper Portal Vein Sinusoids

32. Portal-Systemic (Caval) Anastomoses When portal circulation through the liver is diminished or obstructed because of liver disease or other problems (alcoholism, cancer and hepatitis), blood from the GI tract can still reach the right side of the heart via the Inferior Vena Cava (systemic) by collateral routes. The blood flow reverses direction from portal circulation into the SYSTEMIC VEINS because the portal veins have no valves. Portal hypertension from obstruction of the Portal Vein (e.g., liver cirrhosis) causes an enlargement of anastomotic sites between the portal and systemic veins which can become varicose possibly resulting in hemorrhage. These are problematic areas. See handout Unit 19, Moore page 305-308

33. 1. Esophageal varices: Esophageal Veins: Azygos (Systemic) Left Gastric Vein: Portal 3. Rectal hemorrhoids Inferior Rectal Vein: Systemic Superior Rectal Vein: Portal 2. Paraumbilical veins forming caput medusae Epigastric Veins: Systemic Paraumbilical Veins: Portal Plate 312 Portal-Systemic Anastomoses Esophageal varices can be fatal

34. Seen here is "caput medusae" which consists of dilated veins seen on the abdomen of a patient with cirrhosis of the liver. Also note “Ascites”

35. Here is a varix near the gastroesophageal junction that is dark red/ black because it has been bleeding. (The esophagus has been turned inside out.) Endoscopic views of esophageal varices are shown to the right, with dilated veins bulging into the lower esophageal lumen. varices

36. Varices of gut, butt, and caput…….

37. Cut along the right side of the cecum to expose the Ileocecal orifice/valve and the opening of the appendix Plate 282 The valve may help in preventing reflux into ileum but isn’t much of a sphincter Ileocecal Valve Ileocecal Orifice and Valve Opening of Appendix Ileum Mesentery of Appendix

38. Identify the features of the Colon: Haustra Omental Appendages Teniae Coli Large diameter Free the ascending and descending colons from the paracolic gutters Plate 271 Haustra (sacculations) Omental Appendage Teniae Coli (3 bands) Colon

39. Location of the Appendix - 64% retrocecal Inflammation of the appendix is appendicitis. If the appendix ruptures, peritonitis results and an appendectomy is required. Moore, Page 273-275

40. 3. With a late stage appendicitis, pain is felt over McBurney’s point and there is rebound tenderness. 1. Initially, pain is felt near the umbilicus (T10) with appendicitis 2. This is “referred pain” p. 275 Plate 283 Appendicitis

41. Quiz

42. Patient Symptoms A 32 year old accountant complained of a burning pain in the “pit of her stomach” of ~2 weeks duration. She was a smoker and used NSAID a lot. The pain usually began about two hours after she had eaten and then disappeared when she ate again or drank a glass of milk. Except for mild tenderness in her right upper quadrant, just lateral to the xiphoid process, the PDX results were normal. After tests for H. pylori, radiographs of the upper abdomen, and upper GI studies, a diagnosis of acute peptic ulcer was made.

43. Laboratory/Quiz