Chapter 5: Communication, homeostasis, excretion - Liver Flashcards
Which two sources supply the liver with blood?
Oxygenated via hepatic artery (from heart)
Deoxygenated via hepatic portal vein (from digestive system)
Why does deoxygenated blood from the small intestine enter the liver?
To absorb and metabolise nutrients from the small intestine
Where and how does the deoxygenated blood leave the liver?
Hepatic vein travels to the heart
What do bile salts and bile pigments do? Where are they found?
Gall bladder
Bile salts - help digest fats
Bile pigments - waste product from breakdown of heamaglobin
What is the Liver divided into?
Lobules separated by connective tissue
What are wide capillaries in the Liver known as?
Sinusoids
What are sinusoids lined with?
Incompleted layer of endothelial cells - so blood can reach hepatocytes
Why do hepatocytes have a large surface area?
To maximise exchange of substances
What cells make up the central vein?
Hepatocytes and Kupfer
What are Kupfer cells?
They break down RBC into bilirubin
What does the central vein do?
Removes detoxified substances and metabolic end products
Why are excess amino acids deaminated?
Their amine group is removed to convert Ammonia to Urea
Which is more soluble: Ammonia or Urea?
Ammonia
What functions do hepatocytes carry out?
Storage of glycogen, formation of urea, detoxification
True or false: Glycogen is a polysaccharide
TRUE
Glycogenesis is one of the liver’s key roles. What is it?
The conversion of glucose to glycogen to help regulates blood glucose concentration
What process does Insulin trigger?
Glycogenesis
Give three examples of substances broken down in the liver
Hormones, alcohol, lactate
What is lactate and how is it produced?
Energy-rich compound that can be respired by cardiac muscle - end product of anaerobic respiration
What is lactate converted into in the liver?
Pyruvate
What happens to the pyruvate
Some enters mitochondria to be respired aerobically to provide energy for the rest of the lactate to be converted to glucose
Which enzyme converts ethanol into ethanal?
alcohol dehydrogenase
How does alcohol cause fatty liver?
Ethanol generates large amounts of ATP so hepatocytes don’t metabolise as much fat, instead they store it, causing fatty liver. Hepatocytes aren’t able to carry out normal functions.
How are hormones metabolised?
Peptide and protein hormones are hydrolysed into amino acids which can be converted into urea
