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Gastrointestinal > Pancreatic Secretion > Flashcards

Flashcards in Pancreatic Secretion Deck (30):
1

What are the two components of pancreatic secretion?

1) Aqueous secretion
2) Enzymatic

2

Aqueous secretion comes from where?

Duct cells

3

Aqueous secretion consists of what?

Water and Bicarbonate

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.

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5

The enzymatic portion of pancreatic secretion comes from where?

Acinar cells

6

Acinar cells make up what percentage of the pancreas

80

7

What the hell does the centroacinar cell do?

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

8

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

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9

In the absence of pancreatic secretion, we see?

maldigestion, especially of protein and fat

10

What is the major regulator of pancreatic enzyme secretion

CCK

11

Does the Pancreas contain CCK receptors

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

12

Know the mechanism of pancreatic secretion slide

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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.

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14

Pancreatic secretion depends on what transporter

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

15

What exactly does Secretin do?

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

16

Enzymes are secreted on what cell structure

Rough ER

17

Enzymes are secreted in what way to prevent the degradation

With a leader of Hydrophobic Amino acids

18

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

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

19

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

Transitional elements

20

Transitional elements become-----

smooth golgi vesicles

21

Smooth gologi vesicles become---

Condensing vacuoles

22

RER---Transitional elements---smooth golgi vessicles--- condensing vacuoles

summary so far

23

WHat occurs within the condensing vacuoles

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

24

Zymogen granules do what?

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

25

The type of enzymes released depends on what?

Diet

More protein= More trypsin
More carbs= More amylase

26

Threshold pH for secretin release?

4.5

27

Maximal secretin release

pH 3

28

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

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.

29

What stimulates I cells to produce cck

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.

30

KNOW THAT SECRETIN is POTENTIATED BY CCK

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