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Liver Transplant Focus Note
Hepatic (Liver) Basics
Liver
The liver is a soft, reddish-brown, “wedge-shaped” organ,
weighing between 1.0 and 2.5 kg, located immediately under the
diaphragm on the right side of the upper abdomen in front of
the gallbladder and above the right kidney. It is the largest organ
in the human abdomen and plays a major role in detoxification,
glycogen storage and plasma protein synthesis. It also produces
bile which is stored in the gall bladder.
Fig. 1: Hilum through which the hepatic artery,
portal vein and common bile duct pass.
The liver is unique in that it is supplied by two major blood vessels:
• Hepatic artery (20%); oxygenated blood from the celiac trunk
• Portal vein (80%): delivers venous blood from the digestive
tract so that nutrients can be processed in the liver and toxins
extracted. The portal vein drains into the hepatic venous system
which, in turn, drains into the inferior vena cava.
The liver is the only internal human organ capable of natural
regeneration of lost tissue. As little of 25% of remaining liver
tissue can regenerate into a whole liver.
Fig. 2: Hepatic vasculature divided into right and
left sides.
Gross Anatomy
The liver is divided into four lobes based on surface features. On
the front side a falciform ligament divides the liver into a left
anatomical lobe, and a right anatomical lobe (Fig. 3). On the
backside, there are two additional lobes between the right and
left, the caudate and quadrate lobe.
Functional Anatomy
The central area of the liver where the common bile duct, portal
vein and hepatic artery enter the liver is the hilum (porta hepatic)
(Fig. 1). The common bile duct, portal vein and hepatic artery then
divide into the left and right branches to supply the left and right
lobes (Fig. 2). In a widely used Couinaud or French system, the
functional lobes are further divided into a total of eight segments
based on secondary and tertiary blood vessels. They are Caudate
Lobe (1); Left Lobe (2) (3); Quadrate Lobe (4); Right Lobe (5)(6)(7)
(8) (Fig. 4). Only 20% of an adult’s liver (Segments 2 & 3) is needed
to serve as a liver allograft for an infant or small child.
LiverTransplantBasics(Tx-2-fn)RevC2014USltr
Fig. 3: Left and right anterior lobes of liver.
Fig. 4: Functional segments of the liver.
Hepatic (Liver) Basics cont.
Why Is the Liver Important?
Liver cells (hepatocytes) perform a variety of critical functions including:
• producing and excreting bile used for food digestion. Some of the bile drains directly
into the small intestine, and some is stored in the gallbladder.
• metabolizes carbohydrates produces glucose from certain amino acids, lactate or
glycerol.
• breaks down insulin and other hormones
• metabolizes lipids (fats): (synthesizes cholesterol, produces triglycerides)
Fig. 5: Diseased cirrhotic (scarred)
• produces coagulation essentials
liver. Note the nodular
• neutralizes toxins, medicinal products and hemoglobin
transformation and
• converts ammonia to urea
irregular surface.
• stores glucose, vitamin B12, iron, copper
• breaks down hemoglobin of dead red blood cells and excretes it in bile
Liver Diseases
• Hepatitis: inflammation of the liver; Often characterized by jaundice (icterus) (yellowing of the skin & whites of
the eyes, due to bilirubin buildup)
• Cirrhosis: formation of fibrous tissue in the liver; caused by alcoholism or other toxins, or hepatitis (see Portal
Hypertension below)
• Hemochromatosis: hereditary disease resulting in the accumulation of iron
• Wilson’s disease: hereditary disease in which the body retains copper
• Cancer (hepatocellular carcinoma or cholangiocarcinoma)
• Primary sclerosing cholangities, an inflammatory disease of the bile duct
• Primary biliary cirrhosis, auto-immune disease of small bile ducts
• Budd-Chiari syndrome, obstruction of the hepatic vein due to thrombosis (75%) or compression (25%).
Portal Hypertension
Less then 3% of the liver by weight is normally made up of collagenous (fibrous) material. However, as fibrosis
increases in cirrhosis, a point is reached where portal pressure must increase in order to preserve flow. Hepatic
portal hypertension contributes to fluid accumulation (ascites) in the peritoneal cavity by forcing more fluid across
the liver capsule than the body is capable of draining. Sustained portal hypertension also causes enlargement of
the spleen as well and the proliferation of collaterals which have the tendency to bleed and can divert blood away
from the liver.
REFERENCES
ww.absoluteastromony.com/encyclopedia/l/li/kiver_transplantation.htm
www.absoluteastromony.com/encyclopedia/a/al/allograft.htm
www.transonic.com