Pancreas Liver And Gallbladder Flashcards
What mechanism reduces the hypertonicity of chyme?
Movement of water from ECF into the duodenum
This makes chyme isotonic by when it leaves the duodenum
What part of the pancreas produces enzymes?
What is it stimulated by?
Acinus
Stimulated by vagus nerve and cholecystokinin
Why must proteases be secreted as zymogens into the duodenum?
To avoid auto digestion of the pancreas and pancreatic duct
What do active pancreatic enzymes such as lipase and amylase in the bloodstream indicate?
Pancreatic damage or pathology
Where is secretin secreted from?
What does it do?
S cells of duodenum in response to low pH.
Neutralises acidic chyme
Which blood vessels supply the majority of blood to the liver?
Hepatic portal vein branches (80%)
Majority of liver blood flow is deoxygenated
What makes up a hepatic portal triad?
Portal vein, hepatic artery and bile duct
Outline the system of venous drainage for a hepatic portal triad
Portal veins - central veins - hepatic veins - IVC
Which zone of a liver acinus is most likely to be damaged by ischaemia?
Which zone is most likely damaged by toxicity?
Zone 3.
Zone 1.
Where do bile and pancreatic secretions drain through to reach the duodenum?
Ampulla of Vater and sphincter of Oddi
What is the bile acid dependant component of bile?
What is the bile acid independent component?
Bile acids and pigments secreted by the hepatocytes.
Alkaline secretion secreted by duct cells stimulated by secretin.
What 2 primary bile acids make up bile?
What are bile salts?
Cholic acid,
Chenodeoxycholic acid
Bile salts are bile acids conjugated by the amino acids glycine and taurine.
Why are bile salts better than bile acids?
Bile salts are active at duodenal pHs
Bile salts have an amphipathic structure that allows them to emulsify lipids
What is the function of micelles?
Vehicles to carry hydrophobic lipid molecules through aqueous medium and diffuse across brush borders of epithelial cells
What happen to the products of lipid digestion in the basal epithelial cells of intestines?
Reesterified into triglycerides phospholipids and cholesterol and packaged into chylomicrons
What is the path of chylomicrons around the body starting at intestinal epithelial cells?
Exocytosis from cells - enter lacteals (lymphatic capillaries) - travel through lymphatic system - enter vascular circulation at thoracic duct.
What effect does fibre have on bile salts?
Binds to them and facilitates their excretion in faeces, forcing the liver to produce more and as such reducing plasma cholesterol levels
What is the function of the gallbladder?
Store and concentrate bile produced by the liver,
Release bile when stimulated by CCK causing contraction
What is steatorrhoea?
Lipids in faeces
Pale appearance and foul smell
What risk factors are there for gallstones?
Obesity, Age >40, Rapid weight loss, Caucasian descent, Female.
What causes pigmented gallstones?
What risk factors are there for these?
Bilirubin in the gallbladder.
Haemolysis.
What is Biliary colic?
What characterises this?
Gallstones lodged in cystic duct,
RUQ pain radiating to shoulder tip after meals
Lasts 30 mins to 8 hours
Nausea and vomiting
What characterises acute cholecysitis?
Nausea and vomiting,
Constant RUQ pain and tenderness radiating to shoulder tip
Fever.
What characterises Ascending Cholangitis?
Charcots triad - (RUQ pain and tenderness, jaundice, fever)
Nausea and vomiting
Dark urine and pale stools
