How much do you know about the physiology and function of your body? Sadly, many of us never studied this in school. If you don’t know about your body, how can you keep it healthy? Please read on to learn about the function and dysfunction of the liver, as part of our ongoing series on Ayurveda and the Human Body.
THE ROLE OF THE LIVER
The liver is a complex organ with many functions. Its multiple functions make the liver one of the most important organs of the entire body and its proper function is paramount to good health. The liver is located on the right side of the upper abdomen. A normal sized liver is located mainly under the rib cage though a small portion is palpable just inferior to it.
The Hepatic Vascular System
Blood flows into the liver via the hepatic artery and out of the liver via the hepatic vein. The liver is a storehouse of venous blood. When cardiac demand increases, additional blood enters circulation. Several diseases decrease the ability of venous blood to enter circulation. Cirrhosis of the liver is a common cause of this condition. Any abnormality in the flow of blood through the liver results in ascitis (abdominal swelling). Abdominal swelling due to venous congestion can also occur as a result of congestive heart failure. Abdominal swelling is called ascitis in Western medicine and udakadara in Ayurveda.
Liver cells make bile, which travels to the gallbladder where it is stored until needed for fat metabolism.
The liver plays an important role in carbohydrate metabolism. It is responsible for the maintenance of normal blood glucose levels. The liver stores excess glucose as a form of sugar called glycogen. The body stores enough glycogen to last about one day if needed. Glycogen is converted back to glucose when blood sugar levels fall too low. The stimulus for glycogen breakdown comes from a hormone produced by the pancreas called glucagon. In addition, the liver is also responsible for converting two main dissacharides (fructose and galactose) into glucose. Liver disease often results in an inability to regulate blood glucose levels.
Bile produced in the liver is responsible for breaking down fat into small, tiny globules allowing the enzymes produced by the pancreas to effectively digest them. As much as a liter of bile is produced each day. In addition, when a person eats too much carbohydrate or protein, the body will convert the excess protein and carbohydrate into fat. This occurs in the liver.
Cholesterol, a close friend of fat, is also synthesized in the liver where 80% of it becomes bile and the remainder enters the blood and becomes a part of all the body’s membranes including cell membranes.
During the metabolism of proteins in the digestive tract, ammonia is produced. Ammonia is toxic to the body. The liver is responsible for converting ammonia into urea, which is easily removed by the kidneys. If liver function is compromised, ammonia builds up in the blood. In addition, the liver is capable of synthesizing amino acids and building new proteins as needed. However it can not synthesize the essential amino acids. These must be taken in through diet.
When red blood cells age and break down, the hemoglobin flows to the liver and is broken down into bilirubin. Bilirubin is then excreted into bile and removed from the body. If this mechanism of removal is interfered with or if the body is unable to keep up with the pace of red blood cells destruction, the result is jaundice (a yellowing of the skin and the whites of the eye).
The liver is also responsible for the storage of vitamins A, D, K and B12, the formation of blood coagulants and the storage of iron. In addition, the liver plays an important role in detoxifying the body. Enzymes in the liver alter some drugs and toxins making them easy for the kidneys to excrete as a part of the urine. Some toxins are also excreted into the bile fluid and then excreted as a part of the feces.
Common liver diseases include hepatitis and cirrhosis. Hepatitis is an infection of the liver. Cirrhosis is the deposition of fatty deposits and scar tissue in the liver most commonly secondary to alcohol abuse. Cancer of the liver (hepatocellular carcinoma) is fairly common with about 20,000 new cases diagnosed each year.
Signs and symptoms of liver disease:
One or more symptoms may be present. Other conditions can cause similar symptoms. Complete diagnosis is required before concluding liver function is inadequate.
- Jaundice: This is yellowing of the skin and sclera of the eye due to faulty bile flow bilirubin metabolism.
Abdominal swelling: This is due to poor circulation of venous blood through the liver.
- Poor blood sugar regulation. Hyperglycemia is most common.
- Abnormal bleeding and a failure to clot due to a failure to make clotting factors.
- Fever is possible with infections of the liver (hepatitis).
- Anemia is possible due to B12 depletion.
- Pain in the right upper quadrant of the abdomen.
- Enlargement of the liver may be noticeable on palpation and percussion and is
indicative of cirrhosis.
- General toxicity due to an inability to deactivate and facilitate the excretion of some
- Immune compromise due to an inability to produce certain immune proteins (acute
- Excessive redness of the nose and cheeks, as well as the palms, due to dilated
Ayurvedic theory teaches that the liver (Sanskrit: yakrit) is the site of ranjaka pitta. This is the pitta that is responsible for bringing color to the body. Discolorations in the body, especially those that are yellow or green are due to a disturbance of ranjaka pitta. Thus, jaundice is a condition of ranjaka pitta vitiation. The liver is also considered to have an intimate relationship to the blood. The liver is the organ of the raktavaha srota or the vessels that carry the blood. Blood (rakta) is the carrier of heat in the body. Thus, as excessive heat (pitta) builds up in the liver, it is transferred into the blood (rakta) and distributed throughout the body. One sign of this is excessive redness of the complexion, a sign that bhrajaka pitta is vitiated. Another sign is fever. The connection of the liver and blood is also seen when the liver is unable to effectively remove toxins from the body. In this event, toxins build up in the blood and travel along with excessive heat throughout the body. Looking for a place to escape, the toxins and heat are excreted through the sweat and sebaceous glands (svedavaha srota) vitiating bhrajaka pitta and resulting in acne.
Excerpt from “Textbook of Clinical Ayurvedic Medicine,” by Dr. Marc Halpern, Founder of the California College of Ayurveda (our second year textbook).