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Hepatic portal system is a complex system that contains all the veins, capillaries, and other important organs to circulate blood throughout the body. It comprises of the hepatic portal vein and its tributaries.
- The function of the hepatic portal system is to carry nutrients from the digestive tract to the liver after a meal.
- It is used to store and metabolize the enzymes in the body.
- The portal system is an arrangement through which blood is collected from one set of capillaries.
- It passes blood through a large vessel.
- Later it is transferred to another set of capillaries before returning to the blood circulation in the body.
- The system is responsible for supplying the deoxygenated blood to the liver.
- Hepatic Portal System purifies the blood before it is transported to the heart.
- A system of blood vessels that starts and ends in capillaries is called a portal system.
- It connects the colon, stomach, spleen and pancreatic capillaries to the liver capillaries.
- A cough syrup is taken orally as it needs to be metabolised by the liver.
Key Terms: Hepatic Portal System, Blood Vessels, Veins, Human Body, Capillaries, Heart, Liver, Organs, Nutrients, Stomach, Spllen, Enzymes, Pancreas, Diseases
Hepatic Portal System
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The hepatic portal system is a complex system of hepatic portal veins and their capillaries, also known as the portal vein system. A portal system is where the veins begin and end in the capillaries.
- Hepatic Portal System supplies deoxygenated blood to the liver for purification before it is transported to the heart.
- It is the venous system that includes the portal vein and its tributaries.
- The portal system direct blood from the gastrointestinal tract area between the esophagus and rectum.
- It also includes venous drainage of complementary organs such as the spleen, rectum, and pancreas.
- The hepatic portal vein supplies about 75% of the blood required by the liver.
- The remaining 25% is supplied by the hepatic artery.
- Blood of the hepatic artery is enriched with oxygen but poor in nutrients compared to that supplied by the hepatic portal vein.
Hepatic Portal System
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Functions of Hepatic Portal System
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Hepatic Portal System is a part of the circulatory system and is crucial for the normal functioning of the body. There are other venous systems in the body known as the portal vein system.
- It is the largest vein in the abdominal cavity.
- The system carries the blood from the spleen and the gastrointestinal tract to the liver.
- The hepatic veins begin at the junction of the spleen and superior mesenteric veins.
- Blood from the cyst veins and the inferior, mesenteric, and gastric veins are drained through the hepatic vein.
Diseases affecting the liver portal system should be identified and treated as soon as possible. If left untreated, they can be fatal. Medical conditions such as portal hypertension caused by cirrhosis can affect the hepatic portal system.
- The blood is drained from the digestive tract to the liver.
- The system contains substances that are absorbed in the small intestine.
- It pass through the liver before returning to the heart.
- The system is designed to remove toxic substances from our bodies.
- This system occurs in all vertebrates.
- The entire gastrointestinal tract is not part of this system.
- It extends from the lower part of the esophagus to the upper part of the anal canal.
Veins of Hepatic Portal System
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The veins of the hepatic portal system are:
- Superior Mesenteric Vein
- Hepatic Portal Vein
- Inferior Mesenteric Vein
- Splenic Vein
Hepatic Portal System
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Significance of the Hepatic Portal Vein System
The significance of the hepatic portal vein system is as follows:
- The hepatic portal vein carries 75% of the hepatic blood flow and is, therefore, of critical importance.
- It is not a real vein because it does not carry blood directly to the heart.
- The system supplies the veins with metabolic substrates.
- It also ensures that the food ingested is processed by the liver first before it enters the systemic circulation.
- In this way, the ingested toxins are detoxified by the hepatocytes.
- It also ensures that the liver is the first organ after the intestine to take in nutrients.
- The portal vein system captures and redirects substances from the digestive organs.
- It is responsible for draining blood from the gastrointestinal tract into the liver.
- Before it is released into the bloodstream, the liver absorbs more nutrients to process or store for cellular use.
Things to Remember:
- Hepatic Portal system is the system where the veins of the body begin.
- It supplies the deoxygenated blood to the liver to purify the blood before it is transported to the heart.
- The portal system is the venous system that includes the hepatic portal vein and its tributaries.
- The Hepatic system is made up of the superior mesenteric vein, hepatic portal vein, the inferior mesenteric vein, and splenic vein.
- Hepatic portal vein carries 75% of the hepatic blood flow and is therefore of critical importance.
Sample Questions:
Ques. What is the importance of the hepatic portal system in the circulatory system? (4 marks)
Ans.The importance of the hepatic portal system in the circulatory system are:
- Blood that comes out of the digestive tract contains glucose, amino acids, and other nutrients.
- The liver absorbs excess fat and glucose that are used at the time of starvation when the blood flows through the administration.
- Harmful nitrogenous wastes such as ammonia are converted into urea, which is then excreted by the kidney.
- The liver produces proteins that are transported through the bloodstream (e.g. fibrinogen for blood clotting).
Ques. Write a brief note about the following: (A) Hypertension (B) Coronary artery disease? (4 marks)
Ans. (A) Hypertension: High blood pressure will harm the heart, brain, kidneys, and eyes. High blood pressure is the most typical illness of the heart and blood vessels.120/80 is considered normal. If it exceeds 140 mm Hg and 90 mm Hg, it is called hypertension or high blood pressure.
Causes of Hypertension:
- Coronary artery obstruction.
- Smoking makes the heart rate faster. It narrows the blood vessels and thus the blood pressure increases.
(B) Coronary Artery Disease (CAD): It is caused by the build-up of fatty substances in the arterial wall that causes atherosclerotic plaques. It completely blocks the artery, causing a heart attack.
Ques. Where does the Hepatic portal start from? Give a detailed explanation of the process? (5 marks)
Ans. The hepatic portal system begins in the digestive system or gastrointestinal tract and ends in the liver. The parts from which it collects venous blood are the lower esophagus, stomach, duodenum, jejunum, ileum, large intestine, and spleen. The blood drawn from these parts contains all substances that are absorbed from the digestive tract.
- The organ in the body that is primarily responsible for eliminating waste products from our body is called the kidney.
- The organ responsible for digesting food, storing energy, and removing toxins from the body is the liver.
- There is no connection between the transport of substances from the kidney to the liver or vice versa.
- The hepatic artery is the way blood reaches the liver and supplies more oxygenated blood from the lungs.
- The liver's central hepatic vein carries deoxygenated blood, which then leaves the liver and travels to the heart.
The organ in the human body that produces waste products such as urea is the liver. The formation of urea occurs when amino acids that are present in excessive amounts are broken down in the liver. A high level of urea is toxic to the body and is therefore transported from the liver to the kidneys via the circulatory system.
Ques. What is the significance of the AV node and the AV bundle for cardiac function? (5 marks)
Ans. The Atrio Ventricular (AV) node is located in the right atrium near the base of the interatrial septum, which separates the right atrium from the ventricle and leads to the right atrium from the ventricle. Bundle of His carries heart impulses from the atria to the ventricles.
- As the bundle of His crosses the ventricle along the interventricular septum, it divides into two branches, the right and left ventricles.
- They form a network of Purkinje Fibers that penetrate the myocardium.
- The atrial contraction initiated by the excitation wave of the sinus node (SA node) stimulates the AV node, causing the ventricles to contract by the bundle of His and Purkinje Fibers.
- Therefore, the atrioventricular node and bundle play a role in the contraction of the ventricles.
Ques. How are heart sounds made? (2 marks)
Ans. Heart sounds are made from blood flowing through the chambers of the heart as the heart valves open and close during the heart cycle. The vibrations of these blood flow structures generate audible noises. The more turbulent the blood flow, the more vibrations are generated.
Ques. What are the functions of hepatic portal system? (3 marks)
Ans. The functions of hepatic portal system which are as follows:
- Hepatic portal system is used for draining blood from the spleen .
- It controls the functioning of the gastrointestinal tract to the liver.
- The system carries absorbed substances from intestine to liver.
- It is used to detoxifies the deoxygenated blood.
- The system is used to expel toxic substances from the body.
Ques. Name the veins of hepatic portal system? (2 marks)
Ans. The veins of hepatic portal system are as follows:
- Superior Mesenteric Vein
- Hepatic Portal Vein
- Inferior Mesenteric Vein
- Splenic Vein
Ques. Explain the importance of hepatic portal system? (4 marks)
Ans. The importance of the hepatic portal vein system is as follows:
- The hepatic portal vein carries 75% of the hepatic blood flow and is, therefore, of critical importance.
- It is not a real vein because it does not carry blood directly to the heart.
- The system supplies the veins with metabolic substrates.
- It also ensures that the food ingested is processed by the liver first before it enters the systemic circulation.
- In this way, the ingested toxins are detoxified by the hepatocytes.
Ques. What is the difference between hepatic portal vein and hepatic vein? (4 marks)
Ans. The difference between hepatic portal vein and hepatic vein are as follows:
| Hepatic Portal Vein | Hepatic Vein |
|---|---|
| Hepatic Portal Vein is originated from the capillary bed from the stomach. | Hepatic vein is originated from the capillary bed from the liver. |
| It is used to carry blood from gastrointestinal tract to the live | It is used to deoxygenate blood from liver. |
| It drain blood from spleen. | It does not drain blood from spleen. |
| Hepatic Portal Vein terminates at liver sinsoids. | Hepatic vein terminates at posterior vena cava. |
Ques. What will be the output when hepatic portal vein becomes non-functional? (2 marks)
Ans. The liver loses about two thirds of its blood supply when portal blood flow is disrupted. Interestingly, people with this disease are generally asymptomatic and the condition is well tolerated; nonetheless, sudden arterial obstruction invariably causes significant hepatic dysfunction, which can occasionally be fatal. The system is designed to remove toxic substances from our bodies. This system occurs in all vertebrates.
Ques. What are the disorders of hepatic portal system? (2 marks)
Ans. The disorders associated with hepatic portal system are as follows:
- Portal Hypertension
- Prehepatic of nerves
- Chronic Pancreatitis
- Cirrhosis
- Hepatic Fibrosis
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