Portal Vein And Portal Systemic Anastomoses

Question 1

The portal vein is small but long. True or false?

Answer 1

False, it is large but short

Question 2

Length of the portal vein

Answer 2

About 5 cm long

Question 3

The portal vein is formed…

Answer 3

…behind the neck of the pancreas by the union of the superior mesenteric vein and the splenic veins

Question 4

The portal circulation begins as ___ and ends in ___

Answer 4

Begins in a capillary plexus in the organs it drains

Ends in a capillary circulation within the liver- venous sinusoids of the liver

Question 5

The portal vein drains poorly oxygenated but nutrient-rich blood. True or false?

Answer 5

True

Question 6

Organs drained by the portal vein

Answer 6

• The gastrointestinal tract (from the lower end of the esophagus to the upper end of the anal canal)
• The pancreas
• Gallbladder
• Bile ducts

Question 7

There no communications between the portal venous system and the systemic venous system. True or false?

Answer 7

False, there are

Question 8

Direct route of blood in the portal vein or portal circulation

Answer 8

Under normal conditions the portal venous blood traverses the liver and drains into the IVC of the systemic venous circulation by way of the hepatic veins

Question 9

Portal circulation through the liver can be diminished or obstructed because of…

Answer 9

…liver disease or pressure from a tumor

Question 10

There are collateral routes for blood from the GIT to reach the heart through the IVC. True or false?

Answer 10

True

Question 11

The alternative routes of the portal circulation are available because…

Answer 11

…the portal vein and its tributaries have no valves so blood can flow in a reverse direction to the IVC

Question 12

The volume of blood forced through the collateral routes may be excessive. True or false? What’s the result of this?

Answer 12

True. It results in abnormally dilated veins (VARICES) which can be potentially fatal

Question 13

Sites of portal-systemic anastomoses

Answer 13

• At the lower third of the esophagus
• Halfway down the anal canal
• The anterior abdominal wall

Question 14

Portal-systemic anastomoses in the lower oesophagus =

Answer 14

Oesophageal branches of the left gastric vein (portal system) + Osophageal veins draining the middle third of the esophagus into the azygous veins (systemic system)

Question 15

Portal-systemic anastomoses in the anal canal =

Answer 15

The superior rectal veins (portal system) + middle and inferior rectal veins (systemic system) into the IVC

Question 16

Portal-systemic anastomoses in the AAW 1 =

Answer 16

The paraumbilical veins of the anterior abdominal wall (portal system) anastomosing with superficial epigastric veins (systemic system)

Question 17

Portal-systemic anastomoses in the AAW 2 =

Answer 17

Twigs of colic veins draining the ascending colon, descending colon, duodenum, pancreas and liver (portal system) anastomose with retroperitoneal veins (systemic system) - renal, lumbar and phrenic veins

Question 18

What is Caput Medusa?

Answer 18

Varicose veins radiating from the umbilicus due to the dilation of the veins in portal-systemic anastomoses in the region.

Question 19

What is portal hypertension?

Answer 19

It occurs when scarring and fibrosis from cirrhosis obstruct the portal vein in the liver, causing pressure mount-up in the portal vein and its tributaries, resulting in portal hypertension

Question 20

Tributaries of the portal vein

Answer 20

Left and right gastric veins
Splenic vein
Superior and inferior mesenteric veins
Superior pancreticoduodenal
Cystic vein
Paraumbilical vein