Normal liver circulation involves a dual blood supply, ensuring efficient delivery of nutrients and removal of waste products. The liver receives approximately 1500 ml/min of blood, representing about 25% of the cardiac output. This blood flow is crucial for liver function and overall health.
Blood Supply: A Two-Pronged Approach
The liver's blood supply comes from two major sources:
- Portal Vein (75%): This vein carries nutrient-rich blood from the digestive system, spleen, and pancreas directly to the liver. This blood is rich in absorbed nutrients, which the liver processes and stores.
- Hepatic Artery (25%): This artery delivers oxygenated blood from the heart to the liver, providing the oxygen necessary for its metabolic activities.
The combined blood flow from the portal vein and hepatic artery enters the liver's sinusoids, tiny channels that allow for close contact between blood and hepatocytes (liver cells). This intimate contact facilitates the exchange of substances between the blood and liver cells. After passing through the sinusoids, the blood collects in the hepatic veins and eventually drains into the inferior vena cava, returning to the heart.
Blood Flow Volumes: A Closer Look
Multiple sources indicate a total hepatic blood flow ranging from 800 to 1200 mL/min, or approximately 100 mL/min per 100g of liver wet weight. One study even specifies a range of 100–130 ml/min per 100 g of liver, or 30 ml/min per kilogram of body weight. These variations may be due to factors like body size, metabolic activity, and health status.
Bile Flow: A Crucial Component
While not directly part of blood circulation, bile flow is intimately linked to liver function. Bile, produced by the liver, plays a vital role in digestion and fat absorption. Its proper flow is essential for liver health; obstructions can lead to problems like cholestasis ("chole" referring to bile and "stasis" meaning "not moving").
Importance of Normal Liver Circulation
Maintaining normal liver circulation is essential for numerous bodily functions, including:
- Nutrient Metabolism: The liver processes nutrients from the digestive system.
- Waste Removal: The liver filters toxins and waste products from the blood.
- Protein Synthesis: The liver produces essential proteins.
- Bile Production: Bile aids digestion and fat absorption.
Disruptions in liver circulation, as seen in conditions like cirrhosis, can severely impair these functions and lead to various health complications.
