Liver

• What is excretion 


  The removal of waste products of metabolism from the body
• What are the 3 main excretory products in mammals

  Co2

  nitrogenous waste

  bile pigments
• What is nitrogenous waste


  All mammals produce urea in the lived passed to the kidneys and secreted as urine
• What are bile pigments

  Produces from the breakdown of haemoglobin or old red blood cells in the liver. They pass to the gall bladder for temporary storage
• Why is the release of faeces called egestion not excretion

  It has never been involved in metabolic reactions it is simply just undigested food which never enter the bloodstream
• 1. hepatic vein
  2. vena cava
  3. aorta
  4. gall bladder
  5. hepatic portal vein
  6. hepatic artery

  
• What is the hepatic artery

  Carries oxygenated blood from the heart to the liver
• What is the hepatic portal vein

  Carries deoxygenated blood high in absorbed nutrients from the duodenum
• What is the hepatic vein

  Carries deoxygenated blood away from the liver to the heart. Sinusoids empty into branches of the hepatic vein
• What are the two main cells in the liver

  kupffer cells and hepatocytes
• What is a hepatocyte

  Liver cell that are metabolically active so contain many mitochondria and involved in metabolic functions like cholesterol synthesis
• What is a kupffer cell


  A type of macrophage which moves around in the sinusoids and clean the liver by braking down RBCand protects the liver from diseases
• What is another name for liver cells

  Hepatocytes
• What is liver tissue made up of

  cylindrical structures called Liver Lobules
• What are liver lobules made up of

  Sinusoids and canaliculi
• How does blood get into the liver lobules

  Branches from the hepatic artery and hepatic portal vein carry blood in and it passes along sinusoids
• What happens when the blood from the hepatic artery and hepatic portal vein mix

  It produces oxygenated blood which is high in nutrients
• What happens to the blood once it has mixes

  It travels down the sinusoids to the hepatic vein passing close to hepatocytes which removes the oxygen and relaxes carbon dioxide and detoxify blood as it flows past
• Where do the sinusoids empty

  Into the branches of the hepatic vein lying at the centre of each lobule called the central vein
• What produces bile


  The hepatocytes
• Where does the bike go once produced

  Goes into the canaliculi in the sinusoids and passes out of each lobule via the bile duct
• What is the point at which bile leaves called

  Portal traids
• Why can’t amino acids be stored in the body

  They contain a nitrogen group which makes them alkaline so the pH within the body would become dangerously high
• What is amino acids broken down into

  urea
• What are amino acids broken down into in th deamination reaction

  Ammonia and keto acid
• What stops ammonia from accumulating

  Ornithine cycle
• The stages of the ornithine cycle

  1. Ammonia and carbon dioxide combine with ornithine to produce citrulline and remove a water
  2. further ammonia is added to citrulline producing argine and removing another water
  3. water is added back to argine removing urea in the process and reconverting argine back to ornithine
• How does urea travel

  in the blood to the kidneys where it is filtered out of the blood and removed in urine
• Why Does the liver store carbohydrates

  For regulation blood glucose concentration
• what is glycogen stored in the liver as


  Cytoplasmic granules
• How are toxins produced

  Either by normal functioning cells like hydrogen peroxide or ingested in food like alcohol
• How does the liver modify toxins

  Methylation, oxidation, reduction or adding another molecule
• How does catalase process toxic molecules


  Directly influences hydrogen peroxide by converting it into water and oxygen
• How many hydrogen peroxides can 1 catalase covert in one second

  5 million
• how does cytochrome p450 detoxify substances

  Involved in the breakdown of drugs, their action can interfere and give unwanted side effects
• How is alcohol broken down

  Alcohol is converted into ethanal by alcohol dehydrogenase and then ethanal is converted into ethanote
• How does excessive alcohol consumption cause cirrhosis

  When too much is consumed detoxifying then requires NAD. NAD is also needed to break down fatty acids, so if NAD is breaking down alcohol fatty acids accumulate since they are not broken down
• ornithine cycle

  1. Ammonia
  2. carbon dioxide
  3. water
  4. citrulline
  5. ammonia
  6. water
  7. argine
  8. water
  9. urea
  10. ornithine