Functions of the Liver
Rahul's Noteblog Notes on Gastroenterology Functions of the Liver
Liver Blood Supply:
The liver receives blood from two sources: hepatic artery (oxygenated blood) and hepatic portal vein (deoxygenated blood containing newly absorbed nutrients, drugs, microbes and toxins from the intestine).
Liver Metabolic Functions:
Carbohydrates:
• Liver is important in maintaining normal blood glucose level.
• If blood glucose is low, liver can break glycogen to glucose and release it in blood stream.
• Liver can also convert amino acids and lactic acid into glucose.
• When blood glucose is high, liver converts glucose to glycogen and triglycerides for storage.
• Glycogenesis: Synthesis of glycogen (Older use: synthesis of glucose).
• Glycogenolysis: Breakdown of glycogen to glucose by hydrolysis.
• Gluconeogenesis: Create glucose from molecules that are not themselves carbohydrates.
Fats:
• Hepatocytes store some triglycerides; break down fatty acids to generate ATP.
• Synthesize lipoprotein and cholesterol.
Proteins:
• Hepatocytes deaminate amino acids so amino acids can be used for ATP production or converted to carbohydrates or fats.
• The resulting toxic ammonia is converted to less toxic urea and excreted.
• Hepatocytes also synthesize various plasma proteins.
Digestive functions:
• Hepatocytes secrete bile, a yellow, brownish, or olive-green liquid.
• Bile is partially an excretory product and partially a digestive secretion.
• Bile salts play a role in emulsification.
• Bile's principal pigment is conjugated bilirubin.
• Conjugated bilirubin is broken down into sterobilirubin, which gives feces its normal brown color.
Glycogen and Vitamin Storage:
• In addition to storage of glycogen, the liver is used to store vitamins (A, B12, D, E and K) and minerals (iron and copper), which are released from the liver when needed elsewhere in the body.
Additional Reading:
Basic Gastroenterology
1. Basic Gastrointestinal Physiology
2. Digestion FAQ, Defecation reflex, etc.
3. Digestion
4. Notes on Functions of the Liver
5. Notes on Jaundice
6. Types of Jaundice
7. Diagram of Gastric Blood Supply
8. FAQ on Gastric Digestion
9. Usage of the D-xylose Absorption Test
Gastroenterology Videos
1. Video of Abdominal Examination in a Clinical Setting
Related Topics
1. Gastrointestinal Disorders
2. Hepatobiliary and Pancreatic Disorders
3. Histology of the Digestive Tract I: Oral Cavity
4. Histology of the Digestive Tract II: Esophagus through Intestines
5. Histology of the Liver, Pancreas, and Gall Bladder
6. Abdominal Examination for Internal Medicine
Medical Images
Useful Medical Images & Diagrams (link opens in a new window)
Random Pages:
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