Exocrine Pancreas Flashcards
What is the main function of the exocrine pancreas?
Digestion
Exocrine pancreas is similar to salivary glands. What is the functional anatomy of the exocrine pancreas made up from?
Acini - cavity in gland surrounded by secretory cells
Simple cuboidal epithelium
Several excretory ducts (with cuboidal epithelium lining) combine to make what?
Accessory pancreas ducts
What are the 2 main components of pancreatic juice?
HCO3-
Enzymes
What is the function of HCO3- in pancreatic juice?
Neutralise stomach acid to protect small intestine mucosa
Create correct pH for digestive enzymes
What are the functions of the enzymes in pancreatic juice?
Digest carbohydrates, proteins and fats for absorption in the small intestine
Pancreatic juice has a similar ionic composition to what?
Blood
Describe the ionic composition of pancreatic juice
HCO3- actively transported into duct lumen in exchange for Cl-
Water follows by osmosis
H+ transported into blood (negates alkaline tide)
HCO3- is reabsorbed into acinar cells (when normal flow rate). When high flow rate, not enough time to reabsorbed HCO3- so juice is highly alkaline
Constant Na+/K+
Why are proteases secreted into the stomach in an inactive form?
To prevent auto digestion of the stomach
What does amylase break down?
Starch to maltose
What do lipases/phospholipases break down?
Fats to glycerol and fatty acids
Pancreas juice contains what precursor for the enzyme trypsin?
Trypsinogen
How is trypsinogen converted to trypsin?
By enteropeptidases on the duodenum epithelial surface
What is the function of trypsin? Why do pancreatic cells produce a trypsin inhibitor?
Auto catalysis and activation of other proteases
To prevent auto digestion
What are the three phases of digestion?
Cephalic phase
Gastric phase
Intestinal phase