Gastrointestinal Module #2b Flashcards
What does the Glisson capsule do in the liver?
Sounds liver and contains blood vessels, nerves and lymphatics
What happens when the glisson capsule distends?
Causes pain
What is the functional unit of the liver?
Lobule
How are hepatocytes arranged?
Radially around central vein
Where are capillaries (sinusoids) located in the liver?
Between heaptocytes
From whom do sinusoids (capillaries) receive blood from?
Hepatic Artery
Hepatic Portal Vein
Where do sinusoids (capillaries) drain?
Central vein –> hepatic veins and IVC
Where are bile canaliculi located?
Plates of hepatocytes
Where do the bile canaliculi drain?
Small bile ducts –> eventually make their way into common bile duct
What are the immune/defense cells that line the sinusoids?
Kupffer Cells
Stellate Cells
Pit Cells
Disse Space
What are kupffer cells?
Macrophage (phagocytic) cells that line the sinusoids
What is the function of the kupffer cells?
Phagocytic cells –> RBC breakdown (bilirubin production)
What is clinically important about kupffer cells?
Early response to liver injury/pathology
Responsible for early steps in alcoholic (ethanol) induced injury
1st step in cascade of events leading to fibrosis/cirrhosis
What are stellate cells and where are they located?
Contractile cells
Located in perisinusoidal space
When do stellate cells become activated?
During pathology –> usually store vitamin A when dormant
What is the function of stellate cells when they become activated?
Contraction/relaxation to regulate sinusoidal blood flow
Production of scar tissue (collagen –> fibrosis) in development of cirrhosis
What do pit cells do?
Produce interferon and other immune defense substances
Clinically what is the function of pit cells?
“First line of defense” against tumor formation
Cytotoxic effect on tumor cells
What is the Disse space?
Interstitial space between hepatocytes and sinusoids that drains into lymphatic vesels
Describe the general pathway of bile (start w/ production)
Produced in Liver
Secreted into duodenum
Excreted/reabsorbed
What is the pH of bile?
7.6 - 8.6
What is bile alkaline?
Helps to neutralize stomach acids in duodenum
Describe bile
Alkaline, yellow fluid that is made mostly of water
What are the organic compounds found in bile?
Bile Salts
Cholesterol
Bilirubin
Phospholipids
What is the major organic compound found in bile?
Bile Salts
What are bile salts?
Conjugated bile acids
What does bile do?
Emulsifying agent to assist in breakdown of fats for absorption in small intestine and formation of micelles
What is bilirubin?
Yellow pigment from RBC (heme portion) degradation
Where is bile secreted into initially?
Canaliculi
Where do canaliculi eventually drain into?
R/L hepatic duct –> common hepatic duct
How much bile will flow into the gall bladder during fasting?
75%
What happens to the 25% of bile that doesn’t flow into the gall bladder during fasting?
Continue on and flow into the duodenum via common bile duct