Physiology Pancreatic and Biliary Functions Flashcards
What is the total volume of bile and pancreatic secretions?
1 L bile
1 L pancreatic juice
Therefore total is 2L
What is the function of bile salts vs bile pigments?
Bile salts = fat digestion
Bile pigments = excreted
How much pancreatic (exocrine) secretions are produced per day?
1 L
Describe the pathway of how pancreatic secretions reach the duodenum.
Produced in acini (glands) –> ducts –> common bile duct –> sphincter of oddi –> duodenum
Name the two major components of exocrine pancreatic secretions.
Alkaline fluid - HCO3 (ducts) Digestive enzymes (acinar glands)
Describe the alkaline fluid from the pancreas and its function.
Isosmotic with plasma
HCO3 rich - concentration increases with flow rate
Neutralizes acid chyme from stomach to optimize pH for pancreatic enzymes (6.7 - 9)
Which cells produce the isosmotic HCO3 rich solution?
Duct cells
Cl/HCO3 exchange - final composition variable
Name some examples of the digestive enzymes secreted by the pancreas.
Amylytic - pancreatic amylase
Nucleolytic - ribonuclease, deoxyribonuclease
Lipolytic - lipase, phospholipase
Proteolytic - trypsin, chymotrypsin, carboxypeptidase
What is produced in the acinar cells?
Inactive precursors of enzymes.
Released by exocytosis.
What activates trypsinogen to trypsin and what is the importance of this?
Enterokinase activates trypsinogen to trypsin.
This activates the other proenzymes
How are pancreatic secretions regulated?
Secretion increases during a meal - due to cephalic/gastric phases
Intestinal phase is dominant
Acid causes secretin to be released
Food causes CCK to be released.
What effect does increased duodenal activity (acid chyme from the stomach) have on the pancreas?
Causes secretin to be produced by duodenal cells (S cells)
What does secretin stimulate?
Production of HCO3 in ducts
What effect does the arrival of fatty acids, amino acids and sugars have on the pancreas?
Leads to production of cholecystokinin (CCK) by endocrine cells in duodenum (I cells)
What does CCK stimulate?
Acinar cell enzyme secretions