Question

Which of the following is the vascular connection that exists between digestive tract and liver?
1. Hepatopancreatic duct
2. Renal portal system
3. Hepatic sinusoids
4. Hepatic portal system

Answer 1

Correct Answer - Option 4 : Hepatic portal system

Concept:

• Portal system: When the vein of an organ does not reach the heart directly but it divides into small capillaries in any other organ, and then the vein of that organ supplies or transport blood to the heart, this type of system is called the portal system.
• It is of three types:

1. Renal portal system
2. Hepatic portal system
3. Hypophysial portal system

Explanation:

• Hepatic portal system: It is a portal system that brings venous blood from the digestive tract, spleen, pancreas, and gall bladder to the liver for the extraction of nutrients and other metabolites by breaking up into single-celled thick capillaries and sinusoids.
• It is formed of the following veins:

1. Hepatic portal vein
2. Splenic vein
3. Superior mesenteric vein
4. Inferior mesenteric vein

• The superior mesenteric vein and the splenic vein come together to form the actual hepatic portal vein.
• The inferior mesenteric vein connects in the majority of people on the splenic vein, but in some people, it is known to connect on the portal vein or the superior mesenteric vein.
• Thus, the Hepatic portal system establishes a vascular connection between the digestive tract and liver.

 

• Hepato-pancreatic duct: The bile duct and the pancreatic duct open together into the duodenum as the common hepato-pancreatic duct which is guarded by a sphincter called the sphincter of Oddi.
• Renal portal system: Veins that collect blood from the posterior parts of the body and legs combine to form a renal portal vein. This vein goes into the kidney and divides into numerous small capillaries, the blood gets purified in the kidney. This partly purified blood is then transported to the heart.
• Hepatic or liver sinusoid: It is a discontinuous type of capillary where oxygen-rich blood from the hepatic artery & nutrient-rich blood from the portal vein gets mixed.