Endocrine Pancreas: Insulin and Glucagon Flashcards
The Islets of Langerhans in the pancreas contain what cell types
Alpha, Beta, Delta, F cells
Alpha cells in the islets do what?
Glucagon synthesis
Beta cells in the islets do what?
Insulin Production
Delta cells in the islets do what?
Somatostatin
F cells in the islets produce what?
Pancreatic polypeptide
Where do the alpha cells tend to be located within the islet?
The outside of the cell
Where do the beta cells tend to be located within the islet?
The inside of the cell. Delta cells tend to be in between
What does somatostatin do in the pancreas?
We know that somatostatin is an inhibitory hormone. It inhibits insulin and glucagon production in the pancreas. Works in a paracrine fashione
Insulin synthesis
Proinsulin –> insulin + C peptide
B cells make highly electron dense granules
KNOW
Know that insulin and C- peptide are both packaged into granules and that they are both dumped out in equal molar amounts
truth.
This can sometimes be important clinically. For example, if you have a pt who is insulin dependent but may have some residual B cell function and you want to know how much…you can measure C-Peptide level
Major stimuli for insulin secretion?
Increase in Plasma glucose
Increase in plasma amino acids
Increase in GI hormones
Increase in Parasympathetic NS (Ach)—Better absorption (insulin) when you aren’t stressed
Decrease in sympathetic
Major stimuli for glucagon relase
Decrease in plasma glucose
Increase in plasma amino acids- (If you eat a steak with no bread, so high protein with no carbs, your amino acid levels will rise which will stimulate insulin release and your glucose will plummet. The release of GLucagon prevents sudden hypoglycemia
Do you see changes in peripheral glucagon levels after a big meal?
NO!!! It mostly goes to the liver.
KNOW
Insulin release occurs in what pattern?
Rapid oscillations
