The Role of the Liver
Can you live without your liver? Why or why not?
• You can, but I would say no more than a week max. The liver can loser a little over ¾ of it cells before it stops functioning, plus it is the only organ that can regenerate itself. The liver cleanses the blood of bacteria and foreign material. It is necessary for bile production which ultimately helps emulsify fats which fosters their absorption. The liver conjugates bilirubin with glucuronic acid which is excreted in the bile, without the liver bilirubin would stay unconjugated which when built up would be toxic to cells. It also has many metabolic functions such as helping to regulate blood glucose concentrations, rapid metabolism of fats; all nonessential amino acids are produced in the liver along with plasma proteins in the blood. It produces and removes blood clotting factors, detoxifies the blood, and stores, synthesizes, and transports various vitamins and minerals.
Briefly describe the blood flow to (into) the liver and from (out of) the liver. (This is an important thing to know in order to understand portal hypertension, make sure it’s correct.)
• There are two main blood vessels supplying the liver. The hepatic artery carries oxygenated blood from the aorta. The hepatic portal vein carries nutrient-rich deoxygenated blood from the stomach, intestines, spleen, and pancreas. In the liver, both the hepatic artery and hepatic portal vein branch off and surround each lobule. Each set of hepatic artery and hepatic portal vein branches connected to the hepatic vein via a blood vessel called a sinusoid which runs centrally through each liver lobule. The hepatic vein ultimately drains blood from the liver to the vena cava and general circulation.
What are the major functions of the liver?
• The liver performs over 400 vital functions.
• The liver cleanses the blood of bacteria, foreign material, hormones, drugs, and other poisonous substances are metabolized by the liver into inactive forms for excretion.
• It produces bile, which helps carry away waste and break down fats in the small intestine during digestion.
• It synthesizes fibrinogen(factor I), prothrombin(factor II) , and factors VII, IX, and X. It also removes active clotting factors from circulation and therefore regulates blood clotting.
• All nonessential amino acids are produced in the liver. Amino acids must be deaminated or cleared of ammonia to be used for energy by cells, or converted into carbs or fats.
• It produces all plasma proteins in the blood except gamma globulins.
• Production of cholesterol and special proteins to help carry fats through the body.
• Conversion of excess glucose into glycogen for storage, glycogen can later be converted back to glucose for energy. (Glycogenesis, Glycogenolysis, Gluconeogenesis)
• Processing of hemoglobin for use of its iron content.
Briefly discuss conjugated versus unconjugated bilirubin.
• Bilirubin is formed from the breakdown of hemoglobin by macrophages. It starts as indirect or unconjugated bilirubin which binds to albumin and is NOT water soluble and therefore cannot be excreted by the kidney in the urine. So, the liver fixes this by taking the unconjugated bilirubin and conjugates it with glucuronic acid to form direct or conjugated bilirubin, which IS water soluble. The conjugated bilirubin is secreted into bile and eventually excreted through the digestive system although some conjugated bilirubin returns to the blood and is reflected in the direct serum bilirubin level.

What is prothrombin time and what is its role in the body?
• Prothrombin is a glycoprotein formed by and stored in the liver. The prothrombin time test specifically evaluated the presence of factors VII, V, X, prothrombin, and fibrinogen by counting in seconds how long the liquid part of blood or plasma takes to clot. Normal PT. time is 11-16. Any drop in any of these clotting factors or blood thinning medications will make this time longer.