Human Liver Anatomy, What is A Liver?
Although skin is considered to be the largest organ of the human body, liver is known to be the largest internal organ and the largest gland in the human body. One may wonder about "What is a liver?" and what a purpose it serves. Being a glandular structure, it is an organized group of cells or tissues specialized to secrete or excrete certain substances to be used elsewhere in the body. Glands are broadly classified into two major groups i.e. endocrine and exocrine glands. A normal liver weighs about 1.2 to 1.5 kg and performs both endocrine and exocrine functions.
Location of liver
Liver is located in the right upper quadrant of the abdomen, just beneath the right side of the diaphragm and under the right lower rib cage. Concerning human liver anatomy, it has two major lobes, a larger right lobe and a smaller left lobe that are further subdivided into eight functional segments. Within a minute approximately 1500ml of blood flows through the liver to ensure its efficiency. In part due to its ample blood supply liver is a prime site for metastatic spread of cancer.
Regenerative capacity of liver
The majority of cells in the liver are hepatocytes, the remaining cell types are Kupffer cells, stellate cells, endothelial cells and bile ductular cells. When functional cells (hepatocytes) of liver are lost, not completely understood mechanisms (growth factors, cytokines etc) induce proliferation of the remaining liver cells, that is why when part of the liver is removed surgically or damaged due to any other injury, the remaining hepatocytes can undergo regeneration and thus the complete recovery from the injury can be expected.
Signs of liver disease
Jaundice is the hallmark sign of liver disease and may be the most reliable marker of the severity of the disease. Typical symptoms of liver disease include:
- Icterus (jaundice)
- Poor appetite
- Discomfort or pain in the right upper abdomen
- Intestinal bleeding
- Abdominal distention
Many patients may not have the aforementioned symptoms but the biochemical liver tests will help to confirm the disease.
Risk factors for liver disease
- Alcohol consumption; alcohol is the leading cause of liver disease in many parts of the world followed by hepatitis C and B virus infection. More than two drinks per day in women and more than three drinks per day in men are thought to be associated with increased rate of alcoholic liver disease.
- Recreational drug use, smoking marijuana and snorting cocaine
- Family history of cirrhosis, Wilson's disease, hemochromatosis, diabetes or endocrine failure
- Intimate or occupational contact with individuals with viral hepatitis
- Accidental exposure to blood or needlestick
- Recent surgery
- Transfusion with blood and blood products
- Sexual exposure to patients with viral hepatitis