How the liver works
Anatomy of the liver
The liver is located in the upper right-hand
portion of the abdominal cavity, beneath the diaphragm and on top of the
stomach, right kidney, and intestines. The liver, a dark reddish-brown organ
that weighs about 3 pounds, has multiple functions.
There are two distinct sources that supply blood to the liver:
- Oxygenated blood flows in from the hepatic artery.
- Nutrient-rich blood flows in from the hepatic portal vein.
The liver holds about 13 percent of the body's blood supply at any given
moment. The liver consists of two main lobes, both of which are made up of
thousands of lobules. These lobules are connected to small ducts that connect
with larger ducts to ultimately form the hepatic duct. The hepatic duct
transports bile produced by the liver cells to the gallbladder and duodenum (the
first part of the small intestine).
What are the functions of the liver?
The liver regulates most
chemical levels in the blood and excretes a product called bile, which helps to
break down fats, preparing them for further digestion and absorption.
All of the blood leaving the stomach and intestines passes through the liver.
The liver processes this blood and breaks down the nutrients and drugs in the
blood into forms that are easier to use for the rest of the body. More than 500
vital functions have been identified with the liver. Some of the more well-known
functions include the following:
- Production of bile, which helps carry away waste and break down fats in
the small intestine during digestion
- Production of certain proteins for blood plasma
- Production of cholesterol and special proteins to help carry fats through
the body · conversion of excess glucose into glycogen for storage (This
glycogen can later be converted back to glucose for energy.)
- Regulation of blood levels of amino acids, which form the building blocks
of proteins
- Processing of hemoglobin for use of its iron content (The liver stores
iron.) · conversion of poisonous ammonia to urea (Urea is one of the end
products of protein metabolism that is excreted in the urine.)
- Clearing the blood of drugs and other poisonous substances · regulating
blood clotting · resisting infections by producing immune factors and removing
bacteria from the blood stream
When the liver has broken down harmful substances, they are excreted into the
bile or blood. Bile by-products enter the intestine and ultimately leave the
body in the feces. Blood by-products are filtered out by the kidneys and leave
the body in the form of urine