2.3 Blood Supply to the Gut Tube

Question 1

What are the 3 main branches of the abdominal aorta which supply the gut tube?

Answer 1

• Celiac trunk
• Superior mesenteric artery
• Inferior mesenteric artery

Question 2

At what vertebral level does the coeliac trunk branch off at?

Answer 2

T12 - just below the diaphragm

Question 3

At what vertebral level does the superior mesenteric artery branch off at?

Answer 3

L1

Question 4

At what vertebral level does the inferior mesenteric artery branch off at?

Answer 4

L3

Question 5

Which artery supplies the foregut?

Answer 5

Celiac trunk

Question 6

What artery supplies the midgut?

Answer 6

Superior mesenteric

Question 7

What artery supplies the hindgut?

Answer 7

Inferior mesenteric

Question 8

Name the structures of the foregut

Answer 8

• abdominal part of oesphagus
• stomach
• duodenum until the major duodenal papilla (1st & 2nd part)

Question 9

Name the structures of the midgut

Answer 9

• duodenum after major duodenal papilla (3rd & 4th part)
• jejunum
• ilium
• caecum
• appendix
• ascending colon
• transverse colon (proximal 2/3rds)

Question 10

Name the structures of the hindgut

Answer 10

• transverse colon (distal 1/3rd)
• descending colon
• sigmoid colon
• rectum
• upper part of anal canal

Question 11

Which of the foregut & midgut derived structures are not part of the gut tube?

Answer 11

• liver
• spleen
• gallbladder
• pancreas

Question 12

How does blood from the abdominopelvic gastrointestinal tract drain?

Answer 12

Via a portal system to the liver

Question 13

What is a portal system?

Answer 13

A system of blood vessels which has a capillary network at each end (one organ’s capillaries to capillaries of another organ); blood going from one organ to another without passing through the heart

Question 14

Which 2 veins form the portal vein in the abdominal cavity?

Answer 14

splenic vein & superior mesenteric vein

REVIEW

Question 15

Where does blood from the gut tube superior to the diaphragm, and inferior to the pelvic floor drain via?

Answer 15

Systemic venous system

Question 16

As blood from the gut tube superior to the diaphragm, and inferior to the pelvic floor drains via the systemic venous system, this means that an anastomosis is present at these watersheds, what is this known as?

Answer 16

Porto-systemic (portocaval) anastomoses

Question 17

What are the 4 sites of portocaval anastomoses in the body?

Answer 17

1. Between the Oesophageal Veins (distal end); draining into either the azygos (systemic system) or the left gastric (portal system)
2. Between the Rectal Veins; the inferior and middle veins draining into the IVC (systemic) and the superior rectal vein continuing as the IMV (portal) (when abnormally dilated = haemhorroids)
3. Between the Twigs of Colic Veins (portal) anastomosing with retroperitoneal veins (systemic)
4. Paraumbilical Veins (portal), anastomosing with the Periumbilical Superficial Epigastric Veins (systemic) (when dilated = caput medusae)

Question 18

What is the clinical significance of these portocaval anastomoses?

Answer 18

To provide alternative routes of circulation when there is a blockage in the liver or portal vein