ABDOMINAL CIRCULATION

Question 1

The best collateral circulation between the Celiac trunk and SMA is between these 2 arteries.

Answer 1

The Superior pancreaticoduodenal Artery (SPAA) and Inferior branch (IPAA).

Question 2

A peptic ulcer can endanger what artery that puts a person at risk for GI bleeding?

Answer 2

The gastroduodenal artery located behind the duodenum that branches off from the common hepatic artery.

Question 3

The celiac trunk originates at vertebral level ___ and supplies blood to the ______. The SMA at ___, supplying blood to the _____; and the IMA at ___.

Answer 3

T12, foregut;
L1, midgut;
L3

Question 4

The proper hepatic artery further divides into what 4 arteries?

Answer 4

Right gastric artery (along lesser curvature of stomach),

Right and left hepatic arteries and the Cystic artery

Question 5

The poorest collateral supply is located at the ____ flexure and anastomoses between what 2 arteries? It serves as a connection between the SMA and IMA through the _______ artery.

Answer 5

Splenic flexure;
Between the middle colic artery and left colic artery;
Marginal artery

Question 6

What arteries does the SMA supply blood to?

Answer 6

The IPAA, middle colic A, right colic A, appendicular A, Jejunal AA and Ileal AA.

Question 7

The IMA provides blood to what arteries?

Answer 7

Left colic A, Sigmoid AA, Superior Rectal A

Question 8

The Splenic flexure is a common site of _________ disease due to the poor collateral between the ____ and _____ arteries.

Answer 8

Ischemic Bowel Disease;

Middle and left colic AA

Question 9

What organs drain into the IVC through the canal system? What organs drain into the portal system?

Answer 9

Primary retroperitoneal organs such as the kidney and gonads drain into the IVC. Peritoneal and secondary retroperitoneal organs drain into the portal vein.

Question 10

Describe the portal vein and its significance.

Answer 10

The portal vein is located at the junction of the SMV and the splenic vein, behind the neck of the pancreas. It is located between 2 capillary beds. These beds are between the organs of the GI, the liver and the IVC.

Question 11

What are 2 important features about blood flow in the portal system?

Answer 11

The portal vein and its branches DO NOT have valves and an obstruction to blood flow will reverse the pressure gradient and the direction of flow.

Question 12

Describe the 2 portacaval anastomoses.

Answer 12

1. Rectal wall: backflow of portal system < superior rectal veins < inferior rectal vein (within rectum) < middle rectal vein < iliac vein < IVC < heart.
2. Esophageal branch: backflow of portal system < left gastric vein < esophageal vein < azygos vein < IVC

Question 13

What makes Esophageal varices so dangerous?

Answer 13

The abrasion of food in the esophagus can rupture one of the veins leading to bleeding in the gut tube. This is a very telling sign of portal hypertension.

Question 14

Describe the cause and features of rectal hemorrhoids.

Answer 14

Enlarged veins under rectal mucosa are indicative of portal HTN.

Question 15

Describe Caput Medussae

Answer 15

Vessels that radiate like spiders around the umbilicus are features of late stage portal HTN. Poor anastomoses exist between the paraumbilical veins and epigastric veins.

Question 16

Describe the Transjugular Intrahepatic Portasystemic Shunt and what it treats.

Answer 16

TIPS is used to treat portal hypertension and reduce esophageal varices. It involves sliding a catheter down the internal jugular vein < brachiocephalic vein < SVC < RA < IVC < hepatic vein. Once at the hepatic vein, it burrows through the liver until it reaches the portal vein into which a stent slides along the new pathway. This forms an intra-hepatic portacaval shunt.

Question 17

Describe the lymphatic drainage of the GI tract.

Answer 17

Lymphatics follow vasculature where the preaortic and paraaortic lymph nodes drain into cysternae chelae and the thoracic duct.

Question 18

Describe the procedure and purpose of performing a Resection of the Colon.

Answer 18

If a tumor is present in GI lymph, a surgeon would peel through the White Line of Toldt to recreate embryonic conditions, pull the parietal peritoneum forward and remove the colon and lymphatics (via the separated mesentery).

Question 19

Inferior epigastric vessel is located ______ to the superficial inguinal ring. An indirect inguinal hernia can be felt ______ to this vessel.

Answer 19

Medial;

Lateral

Question 20

What branch of the superior mesenteric artery supplies the appendicular artery?

Answer 20

Ileocolic artery

Question 21

What are the three signs of Portal hypertension associated with the three portal-caval anastomoses? Describe one feature of each.

Answer 21

“Gut-Butt-Caput”

1. Esophageal varices - communication between esophageal vein (portal) and azygos vein (caval); (most telling sign of portal HTN)
2. Internal Hemorrhoids- bright blood with stool (painful defecation)
3. Caput Medussae - between paraumbilican veins and epigastric veins (late-stage portal HTN)

Question 22

What is the significance of Rectal Hemorrhoids?

Answer 22

These enlarged veins under the rectal mucosa are not painful (if above the pelvic pain line) and indicative of portal hypertension due to high blood pressure in the rectal veins.

Question 23

What is the blood flow of a portal caval anastomosis in the rectum?

Answer 23

Portal HTN in the superior rectal veins can backflow via the middle and inferior rectal veins to get back into the caval system. This can result in painful, internal hemorrhoids if found in the rectal mucosa.