The Liver

Garbage Can

If you suffered through eating liver as a child because “it is good for you,” now you can argue another side. On the one hand, the liver has a lot of red blood cells and, therefore, high iron content, which is good for you. On the other hand, the liver is a detoxifying site. It is an organ that the body cannot live without and that cannot be replaced like a kidney.

Gross Anatomy

The liver is located under the diaphragm and takes up a good amount of room, as it is fairly large. There are four lobes, two of which are fairly visible (the right and the left lobes). The other two lobes are “hidden” on the backside of the liver. The gallbladder is also located on the backside of the liver.

The liver is important in both digestion and in metabolism. The main function of the liver is to export bile into the duodenum of the small intestine. There are cells called hepatocytes that produce the bile. This bile is sent to the gallbladder where it is stored. Bile is used to emulsify lipids, meaning to break down fats.

When blood is filtered through, the liver packages fats and fatty acids into storage units for later use. It also breaks down proteins. In doing so, the liver converts ammonia into urea. Ammonia is toxic but urea is not. If ammonia is not converted into urea, the human body goes into a hepatic coma. The liver also breaks down amino acids so that they can be converted to glucose or used to make ATP. Last, but not least, the liver makes clotting proteins to allow the blood to clot.

The liver stores glucose as glycogen that can be released as glucose when the body is in need of it. This is done to maintain homeostasis. In the liver, the body converts galactose (milk sugar) and fructose (fruit sugar) into glucose, the form of C6H12O6 that the body needs for energy. The liver is also the site where many hormones are broken down and packaged so they can be excreted in urine.

Red blood cells only last for about two months. When they begin to degrade, the iron is stored in the liver. This is one of the reasons why it is high in iron. The liver also stores some vitamins, such as A, D, and B12. The liver can store vitamin A for up to two years.

The liver is where the vast majority of cholesterol is made and broken down to become a part of bile. The LDLs (the bad cholesterol) are made in the liver and sent out into the bloodstream and usually end up in fat cells. The HDLs (the good cholesterol) pick up cholesterol from the arteries and cells and take them back to the liver. Cholesterol is made by using the coenzyme acetyl (CoA) in the liver. Bilirubin, which is a byproduct of the breakdown of red blood cells, is processed through the liver and becomes part of bile.

The liver breaks down many drugs to make them inactive so they can be put back into the bloodstream and released in urine. Essentially, the liver detoxifies the toxins put into the body, like hormones from meat or milk, or pesticides from veggies. Excessive detoxification can lead to problems in the liver.

When Things Go Wrong

There are three main problems that can occur in the liver:

• Hepatitis is inflammation of the liver. It is usually from infection caused by a virus (Hepatitis A, B, or C). Hepatitis B and C are very serious and usually last a lifetime. Both require blood-to-blood contact for contamination and are more difficult to contract than Hepatitis A. Hepatitis A is transferred from hand to mouth after an infected person fails to wash his or her hands after going to the bathroom.
• Cirrhosis is usually the result of chronic alcoholism or hepatitis. With this disease, the liver is chronically inflamed and becomes “hard.” Connective tissue in the liver grows faster than the hepatocytes, so there are fewer working cells, rendering the liver less able to work. Eventually, blood flow is reduced and the veins become overworked. Blood begins to backflow and the person may become jaundiced.
• Cancer of the liver can be caused by Hepatitis B or other factors.