Week 20 Flashcards
(164 cards)
What are the functions of the liver?
- Metabolism- interconversion of carbohydrates, fats and proteins- storage of glycogen and Vitamin A.
- Drug processing- metabolism/detoxification/excretion
- Biosynthesis- bile, cholesterol, phospholipids
- Immune function- screening of intestinal blood with Kupffer cells.
How can the blood supply to the liver be described?
Dual
What are the arteries supplying the liver?
Left and Right hepatic
What does the blood from the digestive organs drain into and then go on to form?
Mesenteric veins –> merge into the portal vein –> travels to the liver
What is the functional units of the liver?
Hepatic lobule
What is the general structure of a hepatic lobule?
Hepatocytes occupy bulk, central vein
What is the portal triad?
The hepatic artery, hepatic vein and bile duct
Where is bile produced and how does it get to the gall bladder?
Produced by the hepatocytes, travels down the bile duct
What is the flow of blood from the digestive system to the heart?
- Portal vein
- Hepatic venules
- Filter past hepatocytes
- Drain to central vein
- Hepatic vein
- Inferior vena cava
What are the components of bile?
- Water (97%)
- Bile salts (0.7%)
- Bile acid
- Fats (0.51%) mostly cholesterol
- Bilirubin (0.2%)
How does bile get from the hepatocytes to the bile duct?
Collected into bile canaliculi
What is the main action of bile?
To emulsify fats which aids the function of pancreatic lipase
What are some excretions (waste elimination) in bile?
Steroid hormones
Calcium
Drugs/drug metabolites
Bilirubin
What is Bilirubin?
Bilirubin is converted Haem from dead erythrocytes.
What is the steps from dead erythrocytes to bilirubin excretion?
- Dead erythrocytes are taken from circulation via phagocytosis (including Kupffer cells in the liver)
- Iron and protein recycled, whereas haem is for elimination
- Haem converted to bilirubin
- Bilirubin is transported to the liver and conjugated
- Conjugated bilirubin is secreted in bile
- Bacteria in large intestine metabolise bilirubin to sterobilin (to give faeces its brown colour.
What is the function of the Gall Bladder?
Storage site for bile salts (60ml)
What regulates gall bladder contraction?
Cholecystokinin (CCK)
What is the Sphincter of Odi?
The major duodenal papilla (site at which bile and pancreatic secretions enter the duodenum)
What happens relating to the gall bladder during a non digestive period?
- Sphincter of Oddi is contracted
2. Bile flows from the liver to the gall bladder
What happens relating to the gall bladder during a non digestive period?
- Intestinal phase triggers release of CCK (cholecytokinin) and secretin
- Secretin stimulates the hepatic duct cells to release bicarbonate
- CCK triggers relaxation of the Sphincter of Oddi and contractions of the gall bladder
- Bile is released into the duodenum
How are bile salts recycled?
Transporters in the terminal ileum (end of small intestine) take up bile sales and transport them to the liver via the hepatic portal vein.
What percentage of bile salts are recycled?
95%
What does returned bile salts to the liver stimulate?
The liver to produce more bile salts
What is the importance of recycled of bile salts in drug pharmacokinetics?
Molecules bound to bile salts remain in the body for longer.