The importance of the liver for overall health
The liver is the second largest organ (after the skin) of the human body and probably has the most diverse metabolic activity. It is part of the digestive system and performs many vital functions. Many of these processes happen on membranes, either the plasma membrane or internal membranes of organelles, which are thought to add up to 33,000 square meters of the surface area [Kidd, 1996]. This is one probable reason why supporting healthy membranes through phospholipids may have such a protective effect on the liver.
The blood supply of the liver is different from other organs in that it receives oxygenated blood through the hepatic artery, but also deoxygenised blood from the digestive tract through the hepatic portal vein which is rich in absorbed nutrients and other, potentially harmful, substances which have been absorbed from the intestines. From the hepatic artery and portal vein, blood flows into sinusoids which are endothelium-lined spaces (rather than capillaries), from there into central veins and on into the hepatic vein towards the heart and circulation around the body. In the sinusoids oxygen, nutrients and other substances are absorbed into the hepatocytes (liver cells) lining them, whilst compounds manufactured in the liver and nutrients needed elsewhere are excreted into the blood [Tartora and Grabowski].
This hepatic circulation system is the main reason for the so-called “first-pass effect” of drugs, the concentration and bioavailability of which can be greatly reduced due to the liver metabolising it post absorption [Pond and Tozer, 1984].
The sinusoids also contain Kupffer cells which are part of the immune system. As specialised macrophages, they “tidy up” old white and red blood cells, bacteria and other foreign compounds... continue reading
