liver & metabolism

• How many lobes is the liver divided into?


  Four lobes
• What lobes are visible in the anterior view of the liver?


  The right and left lobes
• What structures are shown in the posterior view of the liver?


  Entry and exit of blood vessels, lymph vessels, nerves, and bile ducts

  
• What are the functional cells of the liver called?


  Hepatocytes
• What unique ability do hepatocytes possess?


  They have the ability to regenerate
• What are sinusoids in the liver?


  Blood vessels that enhance transportation of nutrients into the hepatocytes
• Where do most nutrients go after digestion?


  They are absorbed from the small intestine into the bloodstream
• What is the role of the portal system in relation to the liver?


  It transports absorbed nutrients to the liver for processing, storage, and release
• What does metabolism refer to?


  All the chemical reactions that occur in the body
• What are the two types of metabolic processes?


  Anabolism and catabolism
• What is anabolism?


  The building up or synthesizing of large and complex molecules
• What is catabolism?


  The breaking down of substances to provide energy and raw materials for anabolism
• Why is an adequate energy supply important in very active cells?


  To meet the demand posed by activity
• What is glycogenesis?


  The formation and storage of glycogen from glucose under the influence of insulin
• What stimulates glycogenolysis?


  Glucagon
• What is gluconeogenesis?


  The formation of new glucose from protein and glycerol when there is inadequate glucose available
• What happens during deamination in protein metabolism?


  Nitrogen is removed from ingested amino acids and converted into urea for excretion
• What is transamination?


  A chemical process whereby an amino group is transferred to a ketoacid to form new amino acids
• Where are plasma proteins mainly formed?


  In the liver
• What does lipid metabolism involve in terms of anabolism?


  Producing triglycerides, forming cholesterol, and synthesizing lipoproteins
• What happens during catabolism of lipids?


  Triglycerides are converted to fatty acids and glycerol when an energy source is needed
• What is the role of the liver in drug metabolism?


  It metabolizes drugs into less active substances, more potent forms, or converts pro-drugs to active forms
• What is a potential outcome of drug metabolism in the liver?


  Production of toxic metabolites
• What happens to inactive metabolites in the liver?


  They are eliminated
• What are the main metabolic functions of the liver?


  • Carbohydrate metabolism
  • Glycogenesis
  • Glycogenolysis
  • Gluconeogenesis
  • Protein metabolism
  • Deamination and urea formation
  • Transamination
  • Protein formation
  • Lipid metabolism
  • Anabolism
  • Catabolism
  • Drug metabolism