by Patience Joseph Mamman
The liver is probably one of the many amazing organs in the human body when its functions are clearly understood yet happens to be one of the most misused and abused organs largely due to ignorance. This article hopes to draw back the curtains to help us see what this wonder organ is and what it is capable of doing.
Some facts about the liver
- The liver is the largest internal organ of the body and is located in the right upper quadrant of the abdomen, beneath the diaphragm and is protected by the lower right ribs.
- It also extends across the midline toward the left upper quadrant of the abdomen and weighs about 1.5kg in the average adult.
- The liver is divided anatomically into two lobes and has a rich blood supply obtained from two sources: 1) the portal vein which brings 75-80% of blood to the liver, including blood from the gastrointestinal tract (stomach, intestine, colon) and spleen. It contains 40% more oxygen than blood in the veins returning to the heart. 2) the hepatic artery supplies blood from the heart.
Functions of the Liver.
- It serves as a blood reservoir: Because the liver is an expandable organ large quantities of blood can be stored in it. Its blood volume is about 450mls which is about 10% of total blood volume. This unique ability of the liver is made possible because it contains sinusoids in place of capillaries which are larger and so have the ability to store more blood.
- The liver functions as part of the immune system. The liver sinosoids contain some giant cells called the Kupffer cells. Their job is to capture and ingest any bacteria within the blood coming into the liver from the intestines and systemic circulation.
- It serves as a large storage of essential minerals such as iron which is one of the raw materials for red blood cell production and copper.
- During intra-uterine life it serves as a factory for red blood cell production.
- It is a storage site for Fat soluble Vitamins such as A,D,E as well as folic acid, Vitamin B12.
- It secretes bile and bile salts which are used in digestion of fat.
- The metabolic functions of the liver:
- It helps in the breakdown of carbohydrates into glucose and goes on to store the excess as glycogen. It also has the capacity to regulate blood sugar by releasing stored glycogen back into the blood as glucose in case of low blood sugar and mopping up excess and storing them as glycogen when it is high. This is known as the glucose buffer function of the liver. In the event of extremely low level of glucose liver can convert protein and fat into glucose for use of the body that process is known as gluconeogenesis.
- Fat metabolism: The liver is involved in the metabolism of fat by producing large quantities of cholesterol, phospholipids, bile and lipoproteins that help break down and transport fatty acids to the cells for further oxidation to generate energy or for storage. And as mentioned above the liver can also breakdown fats to produce glucose.
- Protein metabolism: The liver helps to breakdown large molecules of protein into smaller absorbable portions known as amino acids for the body to be able to utilize them. It also uses these ammo acids to synthesize plasma proteins which are essential for optimum body functions. It also converts the ammonia that is released from breaking down protein into urea which is excreted by the kidney in the urine. Ammonia when left in the body is very toxic.
- The liver produces plasma proteins that are needed in blood coagulation in the case of injuries which helps prevent excessive bleeding and even death.
- The liver is involved in breaking down the drugs we ingest into smaller components that can be utilized by the body. Most drugs pass through the liver especially oral drugs through a process known as the ‘first pass effect’. It also removes the toxic part of those drugs or harmful substances and excretes them through the kidney in urine or through faeces.
In conclusion, lifestyles such as excessive alcohol consumption over a long period of time can bring irreversible damages to the liver resulting in destruction of the cellular components and eventual liver failure, likewise excessive and prolonged intake of certain drugs over a period of time can lead to liver failure. Prolonged and untreated infections such as the Hepatitis virus can also pose a huge threat to the well being of the liver. In summary its important that we watch what we take in as most of them could contain harmful substances that will bring harm to the liver.