Liver

Question 1

What are the main metabolic waste products in mammals?

Answer 1

• CO2
  
  • one of the waste products of cellular respiration which is excreted from the lungs
• bile pigments
  
  • formed from the breakdown of haemglobin from old red blood cells in the liver
  • excreted in the bile from the liver into the small intestine via the gall bladder and bile duct
  • they colour faeces
• nitrogenous waste products (urea)
  
  • formed from the breakdown of excess amino acids by the liver
  • all mammals produce urea as their nitrogenous waste
  • fish produce ammonia while birds and inects produce uric acid
  • excreted by kidneys in the urine

Question 2

What is the liver?

Answer 2

• reddish-brown
• major organ in homeostasis
• largest internal organ of the body
• lies below the diaphragm and is made up of several lobe
• damaged area regenerate very quickly

Question 3

What are the vessels connected to liver

Answer 3

• hepatic artery
  
  • supply liver with oxygenated blood from heart
  • so liver has good supply of oxygen for respiration, providing plenty of energy
• hepatic vein
  
  • takes deoxygenated blood away from liver
• hepatic portal vein
  
  • bring blood from the duodenum and ilem (small intestine)
  • therefore branched
  • rich in products of digestion
  • any harmful susbtances are filtered out and broken down straight away
• bile duct
  
  • bile - susbtance produced by liver to emulsify fats
  • takes bile to gall bladder to be stored

Question 4

What is the main structure of the liver?

Answer 4

• the liver carries out many different complex functions
• but the cells are suprisingly simple and uniform in appearance
• made up from heptaocytes

Question 5

How are hepatocytes specialised?

Answer 5

large nuclei

prominent Golgi apparatus

lots of mitochrondira - active cells

Question 6

What are sinusoids?

Answer 6

where the blood from the hepatic artery and the hepatic portal vein is mixed

surrounded by hepatocytes

contain Kupffer cells

Question 7

WHy is it mixed?

Answer 7

mixing increases the oxygen content of the blood from the hepatic protal vein, supplying the hepatocytes with enough oxygen for their needs

Question 8

What are Kupffer cells?

Answer 8

• resident macrophages of liver
• attached to walls of the sinusoids
• remove bacteria
• break down old red blood cells

Question 9

What are canaliculi?

Answer 9

• hepatocytes secrete bile from the breakdown of the blood into spaces called canaliculi, and from these the bile drains into the bile dictules which take it to the gall bladder
• connected to central vein

Question 10

What are the 3 roles of the liver briefly?

Answer 10

• break down excess amino acids
• remove other harmful substances, e.g. ethanol
• store glycogen

Question 11

What are liver lobules?

Answer 11

• liver is made up of liver lobules
  
  • cylindircal structure made of cells called hepatocytes that are arranged in rows, radiating out from the centre
• each lobule has a central vein in the middle that connects to the hepatic vein
• many branches of the hepatic artery, hepatic portal vein and bile duct are also found connected to each lobule