Hepatic Portal System and Hepatic Portal Circulation Overview

The Hepatic Portal System Definition: The hepatic portal system is a system of veins that comprising the hepatic portal vein and its tributaries. Thus It is also known as the portal venous system (it is not the single example of a portal venous system) and splanchnic veins, furthermore, which is not synonymous with hepatic portal system and is imprecise (its means that the visceral veins and not essentially the veins of the abdominal viscera)

The hepatic portal system is a series of veins that carry blood from the capillaries of the stomach, spleen, pancreas, and intestine, to capillaries in the liver. this is a part of the body’s filtration system that main function is to deliver deoxygenated blood to the liver to be detoxified further before it returns to the heart.

The Hepatic Portal System Consists of:

Hepatic portal vein: It forms at the connection of the inferior and superior mesenteric veins. it is the main vein connected to the liver.
Inferior mesenteric vein: This vein takes blood from the rectum and colon and connects with the portal vein.
Superior mesenteric vein: This drains blood from the small intestine and connects with the hepatic portal vein.
Gastrosplenic vein: This tributary is created by the union of the splenic vein from the spleen and also the gastric vein from the stomach. this joins with the mesenteric vein inside the pancreas.
The hepatic portal system is designed to rid the body of toxins, and it can’t detect those which are designed to help it. furthermore, few drugs should be taken under the tongue, through the skin, or via suppository to avoid entering the hepatic system and therefore, being prematurely metabolized in the liver before reaching general circulation (Hepatic Portal Circulation Function).

Hepatic Systems Structure:

Large veins which are considered the part of the portal venous system are the:

• Inferior mesenteric vein
• Splenic vein
• Hepatic portal vein
• Superior mesenteric vein

The superior mesenteric vein and therefore, the splenic vein come together to form an actual hepatic portal vein. The inferior mesenteric vein connects within the majority of people on the splenic vein, however in some people, furthermore, it is known to connect on the portal vein or the superior mesenteric vein.

Roughly, the portal venous system corresponds to areas supplied (provided) by the celiac trunk, the superior mesenteric artery, and therefore, the inferior mesenteric artery.

How Does The Hepatic Portal Circulation Work?

Hepatic Portal Circulation Pathway: The hepatic system is liable for directing blood from parts of the gastrointestinal tract to the liver

Key Terms

Sinusoid: Any of several channels through that the venous blood passes in the various organs.
hepatocyte: Any of the cells in the liver liable for the metabolism of carbohydrate, protein, and lipids and for detoxification.
Hepatic Portal System: In human anatomy, the hepatic system is the system is that the system of veins comprising the hepatic portal vein and its tributaries.

Rat Liver Sinusoid: Sinusoid of a rat liver with fenestrated epithelial tissue cells. therefore, the Fenestrae area unit approx 100nm diameter and curved dimension five(5) microns. The original magazine thirty,000x. Notice that the microvilli of hepatocytes inside the house of Disse external to the epithelium.

The hepatic portal system is that the system of veins comprising the hepatic portal vein and its tributaries. It is liable for directing blood from the region of the gastrointestinal tract between the rectum and esophagus and furthermore, also includes venous drainage from the supplementary organs like the spleen and pancreas. Therefore, It functions to supply the liver with metabolites and ensures that ingested substances are processed in the liver before reaching the systemic circulation, limiting the damage ingested toxins could cause.

The hepatic portal vein supplies regarding 75% of the blood the liver requires, with the other twenty-fifth (25%) supplied by the hepatic artery. Blood from the hepatic artery is oxygenated but therefore, nutrient-poor compared to that supplied by the hepatic portal vein. furthermore, Blood from either source passes into cavities between the hepatocytes of the liver known as sinusoids, so, which feature a fenestrated, discontinuous endothelium allowing for the efficient transfer and processing of nutrients in the liver. therefore, the blood received from the hepatic portal vein can be contaminated with pathogens such as bacteria.

The liver is rich in specialized immune cells called Kupffer cells that detect and destroy foreign organisms. Following processing, blood collects in a central vein which drains into the hepatic vein and finally the inferior vena cava.

Thus, The liver consumes about 20% of the overall body oxygen when at rest. That’s why the total liver blood flow is quite high at about 1 liter a minute and up to two liters a minute. furthermore, That is about a quarter of the average cardiac output at rest.

Key Points

• The hepatic portal system is that the system of veins comprising the hepatic portal vein and its tributaries.
• The liver consumes about twenty percent (20%) of total body oxygen when at rest, that the total liver blood flow is quite high.
• Blood flow to the liver is unique in that it receives both partially deoxygenated blood and oxygenated.

What is Portal Circulation?

The hepatic Portal circulation is the path of blood that flows through a portal system. therefore, due to the direct path of flow, blood flows from organ to organ while not reentry into the systemic circulation first. therefore, in other words, it flows from one organ to another without first returning to the heart.

Where does the Hepatic Portal System Begain and End?

The hepatic portal circulation definition is that flows of blood from the beginning of the hepatic portal system to the end of it. furthermore, It emerges from capillaries of the spleen and organs of the digestive system and ends in.
hepatic sinusoids- special vascular structures in the liver that function such as capillaries.

What is the Liver Porat System?

Liver Function: The liver has many functions, some of which go hand in hand with the hepatic system. because is the liver is a central processing center of substances that enter the body through the digestive tract. that being so, it is more efficient for those substances to pass directly into the liver than for them to first enter the systemic circulation bypassing through veins that carry them to the heart.
There are the following most notable liver functions of this category:

• The metabolism of oral drugs that require chemical alteration in order to become active.
• The biosynthesis of more difficult or complex substances from simpler ones obtained from the diet.
• Immune protection against potentially toxic substances or harmful from the gut, furthermore, including pathogens- most notably by kupffer cells– special macrophages because of the line the sinusoids and which act upon antigens as phagocytes.
• Furthermore, Fat digestion and gut absorption of fat-soluble vitamins by the virtue of enterohepatic circulation.

REFERENCES

1. Hepatic System: https://en.wikipedia.org/wiki/Hepatic_portal_system
2. poratl System Anatomy and related liver Functions: https://prohealthinsight.com/body-systems/digestive-system/hepatic-portal-system-anatomy-and-related-liver-functions/
3. Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates, 2011. ScienceDirect
4. The Circulatory System, Bruce M. Carlson MD, PhD, in The Human Body, 2019