Pancreas Physiology (Costanza/Johnson) Flashcards
function of the aqueous component of pancreatic secretions
neutralize H+
**contains HCO3-
function of the enzymatic component of pancreatic secretions
digestion
cells that secrete the enzymatic portion of the pancreatic secretions
acinar cells
cells that secrete the aqueous portion (bicarb) of the pancreatic secretions
centroacinar cells secrete it and ductal cells modify it
stimulates pancreatic secretions?
inhibits pancreatic secretions ?
How does this compare the the salivary glands?
parasympathetic stim (Ach) and CCK sympathetic inhib
Opposite in the salivary
pancreatic enzymes secreted in active form
amylase and lipases
___ are secreted by the pancreas in there inactive form. Where are they converted into active enzymes?
proteases in duodenum
describe how pancreatic enzymes are synthesized and secreted
made in RER of acinar cells → transferred to the golgi complex → condensed int vacuoles → conc into zymogen granules. They are stored here until stimulated for release (para or CCK)
Pancreatic juice is (hypo, iso, hyper-tonic) solution
isotonic
conc of what ions are the same as in plasma
Na and K
What is the conc of HCO3- in pancreatic juices (compared to plasma)?
low flow: low HCO3
high flow: high HCO3
What is the conc of Cl- in pancreatic juices (compared to plasma)?
low flow: high Cl
high flow: low Cl
The apical membrane of ductal cells contains a _____ exchanger, and the basolateral membrane contains ______ exchanger
apical membrane contains a Cl/HCO3 exchanger,
basolateral membrane contains Na/K ATPase and an Na/H exchanger
the venous blood of the pancreas is (acidic or basic) why?
acidic:
The net result the transport processes is net secretion of HCO3- into pancreatic ductal juice and net absorption of H+ into the blood
rank the following ions in order of those that have the highest conc to least conc in pancreatic juices if there was a high flow rate? low flow rate?
Cl, Na, K, HCO3
high: Na > HCO3 > Cl > K
low: Na > Cl > HCO3 > K
the aqueous and enzymatic componetns of pancreatic secretions are regulated (independently or with the same signals)
independently
what stimulates the secretion of the aqueous component of pancreatic secretions?
H+ in the duodenum
*makes sense by bicarb is the aq part
what stimulates the secretion of the enzymatic component of pancreatic secretions?
products of digestion
**makes sense bc this is the lipases, amylase, and proteases
describe the phases of pancreatic secretions
cephalic: taste, smell, and conditioning → enzymatic secretion
gastric phase: distension of the stomach or vagus N → enzymatic secretion
intestinal:
CCK and para → enzymatic and
Secretin (released in resposne to H+ in duodenum) → aqueous secretion
**Ach and CCK potentiate effects of secretin
describe the regulation of enzymatic secretion
phenylalanine, methionineView drug information, and tryptophan, small peptides, and FA stimulate I cells to make CCK → CCK binds CCKA receptor on ACINAR cells →IP3/Ca→ enzymes secreted
describe the regulation of aqueous secretion
H+ inx in duodenum → S cells secrete secretin → binds receptor on DUCTAL cells → ↑cAMP → aqueous secretion
