liver

• what are the roles of the liver?

  • regulate blood glucose levels by breaking down glycogen store
  • breakdown excess amino acids into urea
  • detoxification eg. breaking down alcohol, hydrogen peroxide, drugs
• why should carbon dioxide be removed from the blood?

  it will react with H+ ions in blood plasma forming carbonic acid which will change the optimum pH for enzyme activity -> slow rate of cell metabolic reactions
• what is a liver cell called?

  hepatocyte
• what are kupffer cells?

  specialised resident macrophages that kill foreign substances
• division of the liver

  A) Lobules

  B) Lobule

  
• two blood vessels provide the liver with blood, these are the...?

  1. hepatic portal vein, branched, wider lumen, which provides liver with deoxygenated blood from the small intestine
  2. hepatic artery, narrower, which provides liver with oxygenated blood from heart
• how does the structure of the hepatocyte relate to its function?

  • lots of mitochondria (because they are metabolically active cells and need more ATP)
  • lots of golgi appartus (to make plasma proteins)
  • a large nucleus
  • SEM ( responsible for detoxification of hydrophobic substances)
  • lysosomes including peroxisomes (that break down hydrogen peroxide)
  • microvilli (increase surface area to increase rate of gas exchange)
• The sinusoids are spaces in the lobule where blood from the hepatic portal vein and the hepatic artery mix together. why?


  to maximise oxygen content of the blood available to the hepatocytes
• why is excretion important in homeostasis?

  homeostasis includes maintaining the correct concentration of substances

  excretion keeps toxic substances at a low concentration
• Structure of the liver and associated blood vessels

  A) bile duct

  B) gall bladder

  C) hepatic artery

  D) hepatic portal vein

  E) aorta

  F) vena cava (vein)

  
• structure of a lobule

  A) Kupffer

  B) hepatic vein

  C) sinusoids

  D) portal

  E) bile duct

  
• lobule section

  A) bile duct

  B) canalicus

  C) hepatic vein

  D) Kupffer

  E) hepatocytes

  F) sinusoid

  G) hepatic artery

  H) hepatic portal vein

  
• what does the hepatic venule do?

  drain away deoxygenated blood from liver
• what is the canaliculus?

  an enclosed space where the bile produced from the hepatic cells is stored. connects to the bile duct
• what does bile do?

  emulsify/ physically breakdown lipids (micelles into smaller ones)
• how does liver bile make rate of lipid digestion faster?

  physically breaks micelles into smaller droplets providing more surface area for lipase enzyme to work
• what are the key functions of a hepatocyte?

  • make bile to digest lipids
  • regulate blood glucose level by converting their glycogen granules into glucose
  • deaminate amino acids
• liver lobule histology

  A) hepatic portal vein

  B) hepatic artery

  C) bile duct

  D) vein

  
• how does the liver convert amino acids into urea?

  1. deamination
  2. ornithine cycle
• what is deamination. give the equation for the deamination process?

  the removal of an amine group from an amino acid

  
• detoxification of alcohol

  A) NAD

  B) NADH+

  C) NAD

  D) NADH+

  E) CoA

  F) acetyl CoA

  G) ethanal

  H) ethanoate

  
• what are sinusoids?

  specialized capillaries with an incomplete basement membrane and fenestrations which allow larger substances such as proteins and blood cells to diffuse through
• outline the ornithine cycle

  A) NH3

  B) citrulline

  C) CO2

  D) Arginine

  E) Arginic succinate

  F) urea

  G) NH3

  H) ATP

  I) AMP

  
• detoxification of an alcohol relies on 2 coenzymes: alcohol dehydrogenase and aldehyde dehydrogenase which are both reliant on NAD
• the product of alcohol detoxification makes ethanoate which is used in what process?

  respiration