Pancreatic Secretion

Question 1

What are the two components of pancreatic secretion?

Answer 1

1) Aqueous secretion

2) Enzymatic

Question 2

Aqueous secretion comes from where?

Answer 2

Duct cells

Question 3

Aqueous secretion consists of what?

Answer 3

Water and Bicarbonate

Question 4

Note that the aqueous secretion of the pancreas, the water and bicarbonate, are secreted at about the same rate as the gastric secretion of the stomach. That is, this pancreatic secretion exists to neutralize gastric acid.

Answer 4

ok

Question 5

The enzymatic portion of pancreatic secretion comes from where?

Answer 5

Acinar cells

Question 6

Acinar cells make up what percentage of the pancreas

Answer 6

80

Question 7

What the hell does the centroacinar cell do?

Answer 7

It regulates the water and electrolyte component of the aquous secretion. Secretin regulates it.

Question 8

Smoking limits pancreatic secretions. May lead to duodenal ulcer because it limits bicard secretion

Answer 8

ok

Question 9

In the absence of pancreatic secretion, we see?

Answer 9

maldigestion, especially of protein and fat

Question 10

What is the major regulator of pancreatic enzyme secretion

Answer 10

CCK

Question 11

Does the Pancreas contain CCK receptors

Answer 11

no. Then how does CCk regulate pancreatic enzyme secretions? Triggers vagal-vagal reflexes in which Ach is the neurotransmitter which stimulates the pancreas.

Question 12

Know the mechanism of pancreatic secretion slide

Answer 12

ok

Question 13

Water is broked down into OH and H, OH combines with CO2 to make bicarb and the bicarb goes out into the lumen while the H goes out into the blood.
Blood of the pancreas has a lower pH.

Answer 13

ok

Question 14

Pancreatic secretion depends on what transporter

Answer 14

Na/K ATPase…the Na has to be pumped out because it is then brought back in to fuel the secondary active transport of hydrogen

Question 15

What exactly does Secretin do?

Answer 15

Activates the CF channel, thus moving chloride into the lumen to fuel the transport of bicarb.

Question 16

Enzymes are secreted on what cell structure

Answer 16

Rough ER

Question 17

Enzymes are secreted in what way to prevent the degradation

Answer 17

With a leader of Hydrophobic Amino acids

Question 18

Enzymes are membrane contained from the moment of their release from the RER…KNOW

Answer 18

this is an important mechanism that prevents teh enzymes from digesting the pancreatic tissue

Question 19

Enzymes are budded off into what when they leave the RER?

Answer 19

Transitional elements

Question 20

Transitional elements become—–

Answer 20

smooth golgi vesicles

Question 21

Smooth gologi vesicles become—

Answer 21

Condensing vacuoles

Question 22

RER—Transitional elements—smooth golgi vessicles— condensing vacuoles

Answer 22

summary so far

Question 23

WHat occurs within the condensing vacuoles

Answer 23

Water is pumped out. Enzymes become proenzymes…these proenzymes are concentrated and stored as zymogen granules.

Question 24

Zymogen granules do what?

Answer 24

They migrate to the luminal aspect of the cell and wait until the secretory stimulus arrives

Question 25

The type of enzymes released depends on what?

Answer 25

Diet

More protein= More trypsin
More carbs= More amylase

Question 26

Threshold pH for secretin release?

Answer 26

4.5

Question 27

Maximal secretin release

Answer 27

pH 3

Question 28

What stimulates S cells to produce secretin during the intestinal phase?

Answer 28

Hydrogen ion, fat, protein entering the duodenum stimulates S cells to make secretin which tehn stimulates duct cells to make water and bicarb in order to neutralize the environment for pancreatic enzymes.

Question 29

What stimulates I cells to produce cck

Answer 29

Fatty acids and amino acids stimulate CCK release from the I cells. This CCK relelase leads to a vagal vagal reflex where Ach is the effector. Initiates the release of enzymes from Acinar cells and also potentiates the effect of secretin on duct cells….leads to maximum HCO3 release.

Question 30

KNOW THAT SECRETIN is POTENTIATED BY CCK

Answer 30

ok