Pancreas

Question 1

composition of the Pancreas

Answer 1

-85% is the exocrine portion -2% is islet of langerhan (endocrine protion) -rest is connective tissue, blood vessels, and nerves

Question 2

main pancreatic duct joins the common bile duct to form…

Answer 2

sphincter of oddi - emptying of ducts into the duodenum

Question 3

big difference between the salivary gland and the pancreas when it comes to their acinus and duct

Answer 3

-in salivary gland, duct modified the fluid produced by the acinus making isotonic fluid to hypotonic fluid -in pancreas - acinus and duct make fluid independent of each other – remains isotonic all the way through

Question 4

big difference between the salivary gland and the pancreas when it comes to their acinus and duct

Answer 4

-in salivary gland, duct modified the fluid produced by the acinus making isotonic fluid to hypotonic fluid -in pancreas - acinus and duct make fluid independent of each other – remains isotonic all the way through

Question 5

difference in fluid produced in the acinus vs. duct in pancreas

Answer 5

acinus - low volume enzyme rich and NaCl rich fluid duct - HCO3 rich fluid

Question 6

enzymes made in the pancreas are essential for

Answer 6

digestion

Question 7

enzymes made in the pancreas are essential for

Answer 7

digestion

Question 8

hormones important for stimulating enzyme secretion in the pancreas

Answer 8

Ach from vagal afferents and CCK

Question 9

how does Ach and CCK work to stimulate enzymes in the pancreas

Answer 9

agonists for increase in intracellular calcium which triggers fluid secretion and exocytosis

Question 10

helps prevent autodigestion of the pancreas

Answer 10

-inactivated enyzmes, zymogens -enzymes in membrane limited vesicle (from synthesis to exocytosis) preventing contact with cytoplasm

Question 11

what changes trypsinogen to trypsin

Answer 11

enterokinase in the small intestine

Question 12

how does conversion to trypsin protect pancreas from autodigestion

Answer 12

conversion happens in the small intestine and not the pancreas so pancreas is protected

Question 13

how does pancreas protect itself from autodigestion just in case trypsin is activated within it?

Answer 13

pancreas produces a trypsin inhibitor so as to protect itself PS also this way trypsin cannot activate other zymogens in the pancreas

Question 14

how does pancreas protect itself from autodigestion just in case trypsin is activated within it?

Answer 14

pancreas produces a trypsin inhibitor so as to protect itself PS also this way trypsin cannot activate other zymogens in the pancreas

Question 15

importance of the duct cells secreting NaHCO3

Answer 15

neutralize gastric acid in the duodenum

Question 16

what happens to cations and anions with increased secretory rate in the pancreatic duct

Answer 16

-cations (Na+ and K+) stay constant -anions HCO3- increases while Cl- decreases

Question 17

explain the pancreatic duct secretion

Answer 17

• HCO3- leaves into the lumen in exchange for Cl- on HCO3-/Cl- transporter
• HCO3- is used to neutralize the gastric acid from stomach
• there is a CFTR channel on the apical side to pull Cl- into the lumen to provide enough Cl- for exchange with HCO3-
• on basal side, there is a Na+/K+ pump and Na+/H+ pump
• the H+ being made in the cell is reabsorbed into the blood to neutralize the alkaline tide made by the HCO3- being excreted due to the gastric acid secretion

Question 18

what happens in people with cystic fibrosis where the CFTR (Cl-) channeling is not working in the pancreatic duct

Answer 18

• the Cl- channel is defective so no Cl- being secreted into the lumen to help operate the HCO3-/Cl- exchanger
• HCO3- cannot be secreted without the Cl-
• so Na cannot follow the HCO3- paracellularly hence no pulling of water into the lumen
• left with dry mucus in lumen and leads to fibrosis of the pancreatic duct

Question 19

most important phase for pancreatic secretion and describes large stimulation that occurs when digestive product and acid appears in the small intestine

Answer 19

intestinal phase

Question 20

what happens in cephalic phase in response to sight, smell, taste, and anticipation of food

Answer 20

secretion of enzymes and bicarbonate

Question 21

what governs the release of secretin

Answer 21

acid load entering the duodenum from the stomach

Question 22

effects of secretin on pancreatic duct

Answer 22

increases the release of cAMP hence activating bicarbonate and fluid secretion

Question 23

big difference in secretin and CCK on where they target

Answer 23

secretin targets the pancreatic duct for release of bicarbonate

CCK targets pancreatic acinus for release of enzymes

Question 24

stimulus for cephalic, gastric, and intestinal phase of pancreas

Answer 24

cephalic - sight, smell, taste of food

gastric - distension

intestinal - AA, FA, Ca2+, H+, distension

Question 25

mechanism that occurs in response to stimulus in cephalic, gastric, intestinal phase

Answer 25

cephalic - vagus

gastric - vagus and gastrin(weak agonist of CCK)

intestinal - CCK, secretin, vagus

Question 26

reason for the falling phase of pancreatic secretion

Answer 26

disappearance of food from the upper part of the small intestine