What is a Portal System?
A portal system is a system in which the veins start and end in capillaries. It delivers nutrient-rich blood to the liver for purification before it is carried to the heart.
Hepatic Portal System and Its Functions
The hepatic portal system is a complex system of hepatic portal veins and their capillaries. It is also known as the portal venous system.
The hepatic portal system is a crucial part of the circulatory system. However, there are other systems of veins in the body that are referred to as the portal venous system.
The hepatic portal vein is the largest vein in the abdominal cavity. It drains blood from the spleen and the gastrointestinal tract to the liver. The hepatic veins begin at the junction of splenic veins and superior mesenteric. The blood from the cystic veins and the inferior mesenteric gastric veins is also drained by the hepatic portal vein.
The ailments that affect the hepatic portal system should be identified and treated as early as possible. If left untreated, might prove fatal. Medical conditions like portal hypertension caused by cirrhosis can affect the hepatic portal system.
The blood that drains from the alimentary canal to the liver contains substances that are absorbed from the small intestine and pass through the liver before going back to the heart. It carries out the main function of further detoxifying deoxygenated blood before reaching the heart. This system is designed to eliminate toxic substances out from our bodies. This system is found in all vertebrates. The entire gastrointestinal tract is not a part of this system. It extends from the lower portion of the oesophagus to the upper part of the anal canal.
Also read: Double Circulation
Veins that make up the Hepatic Portal System
The veins that make up the hepatic portal system are:
- Hepatic Portal Vein
- Splenic Vein
- Superior Mesenteric Vein
- Inferior Mesenteric Vein
Significance Of Hepatic Portal System
- The hepatic portal vein carries 75% of the hepatic blood flow and hence is crucial. It is not a true vein as it does not conduct blood directly to the heart.
- It supplies veins with metabolic substrates.
- It also ensures that food ingested is processed by the liver first before entering the systemic circulation. This way, ingested toxins are detoxified by hepatocytes.
- It also ensures that the liver is the first organ to absorb nutrients after the intestines.
- The portal venous system captures substances from digestive organs and directs them for metabolism.
- It is important since it empties blood from the gastrointestinal tract into the liver. Before releasing into the bloodstream, the liver absorbs nutrients further for processing or storage for cellular use.
Also read: Human Heart
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Frequently Asked Questions
What is the role of the hepatic portal vein?
The hepatic portal vein is the part of the hepatic portal system. It carries blood from the intestines, gallbladder, pancreas and spleen and delivers it to the liver. It contains blood with nutrients and toxins after digestion.
What is the difference between the hepatic portal vein and the hepatic vein?
The hepatic portal vein carries nutrient-rich blood from the intestine and other parts such as the gallbladder, pancreas and spleen to the liver, whereas the hepatic vein carries deoxygenated blood from the liver to the vena cava. The hepatic portal vein brings the blood to the liver, whereas the hepatic vein transports blood from the liver to the systemic circulation and back to the heart.
Which veins drain into the hepatic portal system?
The superior mesenteric vein, the inferior mesenteric vein, and the splenic vein drain into the hepatic portal vein. These veins drain blood from the small intestine, large intestine, gallbladder, pancreas and spleen. The hepatic portal vein carries the blood to the liver. This blood contains nutrients and toxins absorbed from the digested food, which gets processed and filtered in the liver.
What is the hepatic portal vein and what does it empty into?
The hepatic portal vein carries blood from the gastrointestinal tract, pancreas, spleen and gallbladder and drains into the liver. It is not considered a true vein as it transports blood in the liver capillaries and not to the heart directly.
What is the hepatic portal system?
The hepatic portal system is the system of veins that transports blood from the digestive tract to the liver. It consists of the hepatic portal vein and other veins that drain into the hepatic portal vein, viz. the superior mesenteric vein, the inferior mesenteric vein, and the splenic vein. The hepatic portal vein carries blood rich in nutrients and toxins that are processed in the liver and then the hepatic vein carries the blood to the heart through the systemic circulation.
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