Liver is a complex organ in which many vital functions takes place. Thus, being a vital organ, the liver can boast a rich blood supply which is unique to other organs in the body. The arrangement of the feeding vessels, draining vessels as well as within the liver explains the intended function of the liver as being mainly a metabolic process.
For any tissue in the body, there are several essential requirements for it to function normally. These would include,
Good oxygen and nutritional supply
Uncompromised blood flow
The supply:
The liver will have two types of blood supply. One would contain oxygenated blood while the other remains oxygen depleted but concentrated with nutrient elements. Thus, the hepatic artery will supply blood from the main circulation and will contain the oxygenated blood and the Portal vein will carry oxygen depleted blood from the intestinal tract which would contain all the absorbed nutrients, drugs and other elements which is bound to the liver.
It’s been shown that most of the blood supply will be taking place through the portal vein and it approximates to about 75% of the total supply. The other 25% will be from the hepatic artery.
Within the liver:
In the liver, the two vessels will open in to the same blood pool and the two will mix. Thus, the blood supply to the liver would ultimately be partially oxygenated with concentrated nutrients.
A contrasting difference can be seen in the liver when compared to other organs as there are no capillaries or tiny blood vessels seen in the liver. In replace of the capillaries, there are small streams of blood pools known as ‘sinusoids’ which are lined by hepatic cells which readily can absorb the nutrients from the blood and metabolize them inside the cells. The highly complex architecture of the liver cells is designed to reap the maximum efficiency in metabolism and thus its integrity is of vital importance to its function.
The drainage:
Following metabolism, multiple hepatic venules will coalesce to form the hepatic vein which would now contain oxygen depleted blood with normal amounts of nutrients. The hepatic vein will be draining in to the inferior vena cava and thus into the right atrium of the heart.
The minimum number of layers separating the blood and the hepatic tissues has improved the efficiency of uptake and allows uncompromised supply of blood to the hepatic function. It further enhances the tolerability of such a nutrient dense supply which can otherwise block small blood vessels leading to many complications.
