Human Liver, Hepatitis A, Jaundice
The Human Liver
The liver is an organ in vertebrates, including humans. It plays a major role in metabolism and has a number of functions in the body including glycogen storage, plasma protein synthesis, and drug detoxification. It also produces bile, which is important in digestion. It performs and regulates a wide variety of high-volume biochemical reactions requiring specialized tissues.
The adult human liver normally weighs between 1.3 – 3.0 kilograms, and is a soft, pinkish-brown “boomerang shaped” organ. It is the second largest organ (the largest organ being the skin) and the largest gland within the human body.
Its anatomical position in the body is immediately under the diaphragm on the right side of the upper abdomen. The liver lies on the right of the stomach and makes a kind of bed for the gallbladder (which stores bile).
The liver is among the few internal human organs capable of natural regeneration of lost tissue; as little as 25% of remaining liver can regenerate into a whole liver again.
Some functions of liver relating to Hepatitis:
- The liver breaks down hemoglobin, creating metabolites that are added to bile as pigment.
- The liver produces and excretes bile required for dissolving fats.
- Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
- The liver breaks down toxic substances and most medicinal products in a process called drug metabolism. This sometimes results in toxication, when the metabolite is more toxic than its precursor.
- The liver converts ammonia to urea.
Many diseases of the liver are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells; normally, the liver removes bilirubin from the blood and excretes it through bile.
Hepatitis is a gastroenterological disease (inflammation of the liver). It is caused mainly by various viruses but also by some poisons, autoimmunity or hereditary conditions.
A number of liver function tests are available to test the proper function of the liver. These test for the presence of enzymes in blood that are normally most abundant in liver tissue, metabolites or products.
Some chronic forms of hepatitis show very few of symptoms and only present when the longstanding inflammation has led to the replacement of liver cells by connective tissue; the result is cirrhosis (liver scarring). Certain liver function tests can also indicate hepatitis.
Hepatitis A or infectious jaundice is an enterovirus transmitted by the orofecal route, transmitted to humans through methods such as contaminated food. It causes an acute form of hepatitis and does not have a chronic stage.
The patient’s immune system makes antibodies against hepatitis A that confer immunity against future infection. A vaccine is available that will prevent infection from hepatitis A for life.
Normally, it can be spread through personal contact, consumption of raw sea food or drinking contaminated water.
Hepatitis A is transmitted fecal-orally, generally by ingesting contaminated water or food. Strict personal hygiene and the avoidance of raw and unpeeled foods can help prevent an infection.
Infected persons already begin excreting the hepatitis A virus with their stool two weeks after the appearance of the first symptoms.
The time between the infection and the start of the illness can run from 15 to 45 days, and approximately 15% of sufferers may experience relapsing symptoms from six months to a year following initial diagnosis.
Hepatitis A is caused by the Hepatitis A Virus (abbreviated HAV). Only 3 out of 4 people with Hepatitis A have symptoms. Those symptoms may include:
- Jaundice (showing up first as yellow eyes)
- Dark urine
- Loss of appetite
- Stomach ache
Ways to prevent hepatitis A include the following:
- Wash hands with soap and warm water before preparing or eating food, and after sexual activity.
- Keep bathrooms clean and disinfected after every use.
- Cook shellfish thoroughly before eating.
- Drink water from approved sources only.
- Use a dental dam or sheet of plastic wrap during anilingus.
There is no specific treatment for Hepatitis A. Sufferers are advised to rest, avoid alcohol, eat a well-balanced diet, and stay hydrated. Approximately 15% of people diagnosed with Hepatitis A may experience a symptomatic relapse for up to nine months after contracting the disease.
Young children who catch hepatitis A often have a milder form of the disease, usually lasting from 1-3 weeks, whereas adults tend to experience a much more severe form of the disease.
They are often confined to bed and minimal activity for about 4 weeks and have to stop their work for one to three months or longer. Many adults take up to 6-12 months and occasionally longer to recover entirely. Symptoms that may be experienced after the first month or two are low immunity: It is much easier to catch minor infections and for these infections to linger longer than they normally would.
Many people experience a slow but sure improvement, over this later period. They are generally able to function fairly normally, still needing more sleep and reduced athletic activity. It is common for recovering patients to experience occasional “off” days, during which they need to rest more.
Jaundice is a yellowing of the skin, sclera (the white of the eyes) and mucous membranes caused by increased levels of bilirubin in the human body (or the body of another red blooded animal).
When red blood cells die, the heme in their hemoglobin is converted to bilirubin in the spleen and in the hepatocytes in the liver. The bilirubin is processed by the liver, enters bile and is eventually excreted through feces.
Consequently, there are three different classes of causes for jaundice. Pre-hepatic or hemolytic causes, where too many red blood cells are broken down, hepatic causes where the processing of bilirubin in the liver does not function correctly, and post-hepatic or extrahepatic causes, where the removal of bile is disturbed.
Hepatic causes include acute hepatitis, hepatotoxicity and alcoholic liver disease, whereby cell necrosis reduces the liver’s ability to metabolise and excrete bilirubin leading to a build up in the blood.
Jaundice seen in the newborn, known as neonatal jaudice, is common, occuring in almost every newborn as hepatic machinery for the conjugation and excretion of bilirubin does not fully mature until approximately two weeks of age.