The Liver Flashcards
What is the position of the liver in the body?
On the right side of the body, pushing up on the diaphragm
What is the surface structure of the liver?
Larger right lobe and smaller left lobe - separated by ligament
What vessels are attached to the hepatic portal vein?
All the veins of the GI tract drain into the hepatic portal vein
Superior mesenteric vein - small intestine + half of colon
Inferior mesenteric vein - rest of colon
Splenic vein - spleen, pancreas and stomach
How much bile is produced in the liver each day?
1l
What is the function of the gallbladder?
Storage and concentration of bile
How is bile release controlled?
By hormones (e.g. CCK) - released on contraction
What is the function of the hepatic artery?
Supplies oxygenated blood to the liver
What is a portal system?
Two capillary systems in series
What are 2 examples of portal systems that exist in the body?
Hepatic portal system
Hypothalamo-hypophyseal portal system
What vessel is found between the two capillary beds in the hepatic portal system?
Hepatic portal vein
What does the first capillary bed of the hepatic portal system supply? What is absorbed in to the blood here?
Blood to the intestines and stomach, where nutrients/toxins absorbed into blood
What does the second capillary bed of the hepatic portal system supply?
The liver
Nutrients and toxins absorbed in the first capillary bed, taken up by hepatocytes
What does the hepatic portal vein contain?
Water/electrolytes Carbohydrates Proteins Hormones Toxins
What is an example of a toxin found in the hepatic portal vein?
Ammonia
What does the liver do to ammonia?
Convert it to urea that is excreted in the urine
What does the hepatic portal vein NOT contain?
Lipids
Fat soluble vitamins
How are lipids digested?
Digested by lipases and taken up by lymphatics
What are some functions of the liver?
Storage - e.g. Iron and glycogen
Production - of albumin, glycogen, haemotopoiesis in foetus
Breakdown - of drugs, hormones, Hb, RBCs
Filtering - by Kupffer cells (macrophages)
Exocrine function - bile secretion
Endocrine function - produces angiotensin, thrombopoietin
What are the main cells found in the liver?
Hepatocytes
What type of cell renewal do hepatocytes show?
Very quick cell regeneration
Blood is supplied to the liver by which two vessels?
Hepatic artery (25%) - from aorta
Hepatic portal vein (75%) - from gut
What takes deoxygenated blood out of the liver?
The hepatic vein —-> inferior vena cava
What repeating structures does the liver consist of?
Liver lobules
How do the hepatic portal vein and hepatic artery supply blood to the liver?
Through passages called sinusoids towards a central canal
By which cells of the liver is bile produced?
Hepatocytes
Where does bile travel once it is produced by hepatocytes?
In the opposite direction to bile ducts through bile canaliculi
What makes up a portal triad? Where is a portal triad positioned?
Hepatic portal vein
Hepatic artery
Bile duct
Around a lover lobule - surrounding a central vein
What is the space of disse?
Exits between endothelium and hepatocytes - microvilli of hepatocytes extends into this space for increase SA
What are Kupffer cells? Where are they found?
Macrophages found in the lining of sinusoids
What are stellate cells?
Full of cytoplasmic vitamin A
What happens to stellate cells in liver cirrhosis?
Turn into myofibroblasts –> liver fibrosis —> portal hypertension
