Biochem 7 (liver)

Clinical Biochemistry

The Liver

Overview of the Liver

• The liver is a vital organ performing a variety of essential functions.

• Located: Upper right side of the abdomen, just beneath the diaphragm.

Key Functions of the Liver

1. Metabolism

   • Processes nutrients from food into usable forms for energy, growth, and cell repair.

2. Detoxification

   • Filters harmful substances (alcohol, drugs, toxins) from the bloodstream.

3. Storage

   • Stores glycogen, vitamins, and minerals for later use.

4. Bile Production

   • Produces bile to aid in the digestion of fats in the small intestine.

5. Protein Synthesis

   • Synthesizes important proteins, including albumin and clotting factors.

6. Regulation of Blood Clotting

   • Synthesizes clotting factors essential for blood coagulation.

Structure of the Liver

• The liver's structure allows it to perform multiple functions efficiently.

Key Components

1. Lobes

   • Divided into two main lobes: right lobe (larger) and left lobe (smaller).

   • Further subdivided into smaller functional units known as lobules.

2. Lobules

   • Basic structural and functional unit made of liver cells called hepatocytes.

   • Responsible for detoxification, protein synthesis, and bile production.

3. Hepatic Sinusoids

   • Special blood vessels facilitating the free flow of blood, allowing contact with hepatocytes.

   • Site for blood filtration and nutrient/toxin exchange with hepatocytes.

4. Bile Canaliculi

   • Collect bile produced by hepatocytes and transport it to larger bile ducts.

   • Bile may be stored in the gallbladder or secreted into intestines for digestion.

5. Kupffer Cells

   • Specialized macrophages in liver sinusoids.

   • Play an immune defense role by phagocytizing pathogens and dead cells.

Liver and Metabolism

Central Role in Metabolic Processes

• The liver is crucial for various metabolic functions:

1. Carbohydrate Metabolism

   • Processes include glycogenesis, glycogenolysis, and gluconeogenesis.

2. Protein Metabolism

   • Involves deamination of amino acids and the urea cycle.

3. Fat Metabolism

   • Breaks down fats into fatty acids and glycerol; produces lipoproteins and synthesizes cholesterol.

4. Detoxification and Drug Metabolism

   • Filters toxins and pathogens.

   • Kupffer cells play a crucial role in clearing harmful microbes and dead cells from blood.

5. Bile Production

   • Produces bile critical for digesting and absorbing fats and fat-soluble vitamins (A, D, E, K) in the small intestine.