15.4 Excretion, Homeostasis And The Liver Flashcards
What is excretion
The removal of waste products of metabolism from the body
What are the main waste products from metabolism
Co2
Bike products
Nitrogenous waste products (urea)
Where is the liver in the body
Just below the diaphragm in
What supplies the liver with its rich blood supply
2 vessels
Hepatic portal vein
What does teh hepatic portal vein carry
Blood loaded with products from diaphragm
What are the liver cells called and what are there main characteristics
Hepatocytes
Large nuclei, Golgi apparatus and lots of mitochondria
What do hepatocytes surround and what happens in these cells
Hepatocytes surround spaces called sinusoids where blood from the hepatic artery and hepatic portal vein is mixed
What do sinusoids contain
Kupffer cells
These act as resident macrophages of the liver - they ingest foreign particles
What do hepatocytes do
They secrete bile from the breakdown of the blood into spaces called canaliculi where the bile then drains into bile ductules to the full bladder
What are the functions of the liver
Carbohydrate metabolism
Examination of excess amino acids
Detoxification
What is the livers job in carbohydrate metabolism
If insulin levels rise, the liver will stimulate hepatocytes to convert glucose to storage carbohydrate glycogen
How are hepatocytes involved in the deamination of excess amino acids
What is the process called
Transamination
Conversion of 1 amino into another if the body doesn’t have the required balance of amino acids
What is the most important role of the liver in protein metabolism
Deamination
This is the removal of an amine group from a molecule - hepatocytes deaminate excess amino acids by removing the amino group and converting it into ammonia and then urea
What is the conversion of ammonia to urea called
Orinithine cycle
What is detoxification and how are hepatocytes involved
Detoxifying substances
Hepatocytes contain the enzyme catalase that splits hydrogen peroxide into oxygen and water
Hepatocytes contain enzyme alcohol dehydrogenase that breaks down ethanol to ethanal to ethanoate
