Past Papers · SAQ
GI Blood Supply
2021A Q07
Exam questionOutline the anatomy of the blood supply (arteries and veins) of the gastrointestinal system (oesophagus to anus)
CICMWrecks answer
Master answer
Blood supply to the Gastrointestinal system
- Portal circulatory system + arterial blood flow into liver
- 1100ml of portal blood + 400ml from hepatic artery = 1500ml (30% CO)
- Oxygen consumption – 20-35% of total body needs
Arterial Supply
| Aorta | Division / Branches | Organ supplied | |||
|---|---|---|---|---|---|
| Thoracic A. | Subclavian A. | Thyrocervical trunk | Inf. Thyroid A. | Cervical Oesophagus | |
| Bronchial A. | branches | Thoracic Oesophagus | |||
| direct branches | |||||
| Abdominal Aorta / Coeliac | Inf. Phrenic A. | Abdominal Oesophagus | |||
| Anterior branches of Abdominal Aorta | COELIAC TRUNK | Lt. GASTRIC A. | |||
| Foregut (Stomach → major duodenal papilla | |||||
| SPLENIC A. | Short Gastric A.s | ||||
| Lt. Gastroepiploic A. | |||||
| COMMON HEPATIC A. | Hepatic A. Proper | Lt. Hepatic A. | |||
| Rt. Hepatic A. | |||||
| Gastroduodenal A. | Rt. Gastroepiploic A. (gastro-omental) | ||||
| Sup. Pancreatoduodenal A. | |||||
| Supraduodenal A. | |||||
| SUPERIOR MESENTERIC ARTERY | Inf. Pancreaticoduodenal A. | Midgut (Major duodenal papilla → 2/3 of transverse colon) | |||
| Jejunal and Ileal A.s | |||||
| Middle colic A. | |||||
| Rt colic A. | |||||
| Ileocolic A. | |||||
| INFERIOR MESENTERIC ARTERY | Lt colic A. | (2/3 transverse colon → rectum) | |||
| several sigmoid A.s | |||||
| Superior rectal A. | |||||
| Distal Abdominal Aorta | Internal Iliac A. | Middle Rectal A. | Rectum | ||
| Internal Pudendal A. | Inferior Rectal A. | ||||
Venous Drainage
| Organs drained | Branches / Tributaries | IVC | |||
|---|---|---|---|---|---|
| Liver | Hepatic V.s | IVC | |||
| Fundus + L greater curvature Stomach | Short gastric V.s | Splenic V | Portal Vein | Liver parenchyma → Hepatic Veins → IVC | |
| Greater curvature Stomach | Lt. gastro-omental V. | ||||
| Pancreas | Pancreatic V. | ||||
| colon | Lt. colic V. | IMV | |||
| sigmoid | Sigmoid V. | ||||
| rectum | Superior rectal V. | ||||
| Rectum, Colon | direct | ||||
| Rt greater curvature Stomach | Rt gastro-omental V. | SMV | |||
| Pancreas, duodenum | Ant sup pancreatocoduodenal V. | ||||
| Ant and Post inferior pancreaticoduodenal V.s | |||||
| Jejunum | Jejunal V. | ||||
| Ileum | Ileal V. | ||||
| Ileum, colon, cecum | Ileocolic V. | ||||
| ascending colon | Rt. colic V. | ||||
| transverse colon | Middle colic V. | ||||
| pancreas, duodenum | Post Sup pancreaticoduodenal V. | ||||
| stomach | Rt. gastric V. | ||||
| stomach | Lt. gastric V. | ||||
| gall bladder | cystic veins | ||||
| Skin of umbilical region | para-umbilical vein | ||||
Portosystemic Anastomosis
- Areas:
- Lower end of oesophagus
- Upper part of anal canal
- Umbilicus
- Retroperitoneal Bare area of liver
- The gastroesophageal junction around the cardia of the stomach-where the left gastric vein and its tributaries form a portosystemic anastomosis with tributaries to the azygos system of veins of the caval system.
- The anus-the superior rectal vein of the portal system anastomoses with the middle and inferior rectal veins of the systemic venous system.
- The anterior abdominal wall around the umbilicus-the para-umbilical veins anastomose with veins on the anterior abdominal wall.
Past papers