2. Blood supply of Alimentary tract

7. Oral cavity

8. Hard palate Artery Source Greater palatine
Maxillary [external carotid]

9. Tongue Artery Source Lingual External carotid Tonsillar
Facial [external carotid]
Ascending pharyngeal

10. Oropharynx Artery Source Tonsillar Facial Lingual ECA
Ascending pharyngeal
Ascending palatine
Greater palatine
Maxillary [ECA]

11. Soft palate Artery Source Lesser palatine Maxillary [ECA]
Ascending palatine
Facial

12. Oesophagus Area Artery Cervical Inferior thyroid Thoracic
Aorta, bronchial arteries
Abdominal
Left gastric

15. Arterial supply to the gastrointestinal tract
derived from the anterior midline visceral branches of the aorta
usually three anterior branches, the coeliac trunk and the superior and inferior mesenteric arteries

17. The coeliac trunk and its branches
supply from the distal third of the oesophagus to the mid part of the duodenum and all derived adenexae
1. liver,
2. biliary tree,
3. spleen,
4. dorsal pancreas,
5. greater omentum and lesser omentum).

18. The superior mesenteric artery
supplies the tract from the mid second part of the duodenum to the distal third of the transverse colon (jejunum, ileum, caecum, appendix, ascending colon and ileal mesentery).

19. The inferior mesenteric artery
supplies the tract from the distal transverse colon to the upper anal canal.

20. Anastomoses between the vascular territories
around the head of the pancreas and the duodenum between
the anterior and posterior superior pancreaticoduodenal arteries and the inferior pancreaticoduodenal arteries

21. the posterior superior pancreaticoduodenal artery and jejunal arteries
the greater pancreatic artery and jejunal arteries

22. the posterior superior pancreaticoduodenal artery and jejunal arteries
the greater pancreatic artery and jejunal arteries

23. The anastomoses between the territories of the superior and inferior mesenteric arteries are less pronounced and more variable:
the most reliable is the pericolic marginal artery, which runs along the transverse colon.

26. Arterial anastomoses of the stomach
between the oesophageal arteries originating from the thoracic aorta and the vessels that supply the fundus in the region of the cardiac orifice..

27. At the pyloric orifice -some anastomosis between vessels of superior mesenteric artery origin and the pyloric vessels
The major named vessels supplying the stomach form extensive arterial anastomoses both on the serosal surface and around the curvatures.

28. The right and left gastroepiploic arteries and the left and right gastric arteries anastomose freely with each other along the greater and lesser curvatures respectively.

29. Anastomoses also form between the short gastric and left gastric arteries in the region of the fundus, and between the right gastric and right gastroepiploic arteries in the region of the antrum. .

30. In addition to the extensive serosal anastomoses, networks form within the stomach wall at intramuscular, submucosal and mucosal levels

31. A true plexus of small arteries and arterioles is present within the submucosa
It supplies the mucosa and shows considerable regional variation both in the gastric wall and in the proximal duodenum.

32. The rich arterial supply to the stomach ensures that the high mucosal blood flow required for physiological functioning is maintained even if one or more vessels become occluded
The stomach exhibits considerable resistance to ischaemia even when multiple arterial supplies are lost.

39. Arterial anastomoses and the marginal artery of the colon
The marginal artery (of Drummond) of the colon is the name given to the vessel which lies closest to and parallels the wall of the large intestine.
Formed by the main trunks, and the arcades arising from, the ileocolic and right colic, middle colic and left colic arteries.

41. It is most apparent in the ascending, transverse and descending colons
The sigmoid colon has little if any marginal artery.

42. Anastomoses form between the main terminal branches which run parallel to the colon within the mesentery and give rise to vasa recta and vasa brevia to supply the colon.

43. The arc of Riolan is the name given to the arterial anastomosis which is sometimes present in the mesentery between the right side of the transverse colon and the upper descending colon.

44. When present it is formed from a large branch of the middle colic artery which runs parallel and posterior to the middle colic artery in the transverse mesocolon and anastomoses with an ascending branch of the left colic artery close to its origin in the root of the mesentery.

45. This provides a direct communication between the superior and inferior mesenteric arteries.

46. Colonic vascular occlusion
The marginal artery of the colon may become massively dilated when there is chronic, progressive occlusion of the superior mesenteric artery

47. under these conditions it is required to supply the majority of the midgut (except the proximal portion which is supplied by collateral vessels from the coeliac artery).

48. Occlusion of the inferior mesenteric artery does not always result in irreversible ischaemia of the descending and sigmoid colon, because the marginal artery of the colon usually receives an adequate supply from the left branch of the middle colic artery

49. Moreover, the sigmoid arteries may be supplied by the superior rectal artery, which anastomoses with the middle and inferior rectal arteries.
When ischaemia does occur, it is usually maximal in the proximal descending colon because this region is furthest from the collateral arterial supplies.