Module 1: The liver and hepatitis viruses - section 1

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Anatomy

Activity: Lecture presentation
Section Time: Approximately 15 minutes

The purpose of this section is to give participants a basic appreciation of the structure and location of the liver to provide an anatomical context for an understanding of the liver, its function, hepatitis and liver disease.

To facilitate the presentation:

Use Slides 1.2 and 1.3 (Location of the liver) to show abdominal anatomy and location of the liver. Explain that the liver is located under the ribs on the right hand side of the body. It lies just below the lungs under the top of the diaphragm to which it is attached. The diaphragm is the muscle beneath the lungs that regulates our breathing. The liver is partly protected by the rib cage. The ‘Supporting content’ can be used to support more detailed discussion.



Supporting content:

The liver is the largest organ in the body and is located behind the ribcage on the right side of the abdomen. It is shaped like a wedge, weighing between 1.4 and 1.6kg and is about 13cm across and about 18cm along its diagonal. It is divided into two main lobes, the right and the left. The right lobe is the larger of the two and has two smaller lobes itself. All the lobes of the liver perform the same functions.

The primary and most common cells of the liver are called hepatocytes. These are highly sophisticated and identical cells that carry out most of the many functions of the liver. Hepatocytes are split up into groups to form lobules. These are the functional units of the liver. There are up to a million lobules in the liver.

Unlike any other organ in the body the liver has two blood supplies. 25% of blood is supplied from the hepatic artery which delivers highly oxygenated blood from the lungs and 75% comes through the portal vein system which is a network of blood vessels that transports blood through the intestine, stomach, spleen and pancreas and into the liver. All the products of digestion including nutrients and toxins pass into the liver through this route. Once blood had travelled through the liver it returns via the vena cava and to the heart.

The liver is attached to the gallbladder (via the cystic duct). Together they make up the hepatobiliary system. Bile is a greenish digestive juice, which is manufactured inside liver cells. It then passes to the gallbladder for storage until it is needed to help digest fats. When food enters the intestine, bile is secreted into the intestine, via the common bile duct.

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