L30 - GIT Secretions II

Question 1

Prostaglandins increase secretion of what in the stomach?

Answer 1

Bicarbonate

Question 2

The pancreas secretes digestive enzymes as well as what other exocrine secretion?

Answer 2

Bicarbonate

Question 3

The pancreas’ secretions are decreased in chloride but increased in which ion?

Answer 3

Bicarbonate

Question 4

When pancreatic flow rate is high, which ion is secreted more?

Answer 4

Bicarbonate

Question 5

Ductular cells secrete which ion?

Answer 5

Bicarbonate

Question 6

Secretin increases secretion of which ion? CCK increases secretion of which ion? Acetycholine stimulation through the vagal nerve increases production of which ion?

Answer 6

1) Bicarbonate
2) Bicarbonate
3) Bicarbonate

Question 7

In ductular cells, chloride leaks out but is pumped back in through exchange with which ion?

Answer 7

Bicarbonate

Question 8

An increase in calcium concentration causes an increase in secretion of what?

Answer 8

1) chloride

2) zymogen granules

Question 9

CCK and ACh cause an increase in what secretions?

Answer 9

Increase in release of zymogens

Question 10

Pancreatic acinar cells secrete what?

Answer 10

1) Na and Cl ions

2) digestive enzymes

Question 11

If the flow rate is low, what ion is increased in pancreatic secretions?

Answer 11

Chloride

Question 12

The NKCC transpors which ions?

Answer 12

sodium, potassium, and chloride (x2)

Question 13

Why is there an increase in mucus viscosity in cystic fibrosis?

Answer 13

CFTR is a chloride channel which expels chloride ions into the pancreatic ducts. In CF, this does not work, causing a decrease in lumen negativity which will decrease sodium and water transport into the lumen, thus causing decreased watery secretions

Question 14

How much of the pancreatic secretions are accounted for by the cephalic phase of digestion? Gastric phase? Intestinal phase?

Answer 14

Cephalic: 25%
Gastric: 10%
Intestinal: 50-80%

Question 15

What is the major contributor of pancreatic secretion in the cephalic phase?

Answer 15

Autonomic parasympathetic stimulation through the vagal nerve (acetylcholine

Question 16

What are the two major stimuli that control pancreatic enzyme secretion in the gastric phase?

Answer 16

1) gastric distention

2) protein in food

Question 17

In the gastric phase, gastric distention works through what mechanism? What about protein in food?

Answer 17

Gastric distention –> increased vagal response –> stimulated acetylcholine receptors –> increased enzymatic secretion

Protein in food –> increased gastrin –> stimulation of gastrin/CCK receptors –> increased enzymatic secretion

Question 18

What two stimuli produce increased pancreatic secretion in the intestinal phase?

Answer 18

1) digestive products present

2) H+ in the lumen

Question 19

What cells respond to H+ content in the lumen of the intestine? Where are they? What do they secrete? Does this secretion act on the H+ itself or through another mechanism?

Answer 19

1) S cells
2) intestinal mucosa
3) secrete secretin
4) secretin acts to increase bicarb secretion in the pancreatic ductular cells by increasing cAMP

Question 20

What are the two mechanisms that are stimulated when digestive products are present?

Answer 20

1) vagovagal reflex

2) duodenal I cells

Question 21

What do duodenal I cells secrete?

Answer 21

CCK

Question 22

Which digestive products produce the largest CCK response? Smallest?

Answer 22

Largest: FAs
Smallest: Carbs

Question 23

CCK and secretin act by giving the pancreas time to digest food. How?

Answer 23

Inhibit gastric motility and secretion

Question 24

What two proteins drive fluid secretion from the crypts of the small intestine?

Answer 24

CFTR and CACC

Question 25

Which channel in the distal colon is regulated by aldosterone?

Answer 25

ENaCs

Question 26

Which protein concentrates potassium in the cell in the large intestine?

Answer 26

NKCC

Question 27

What are the two types of diarrhea?

Answer 27

1) osmotic

2) secretory

Question 28

What are some bacteria/bacterial toxins which cause diarrhea?

Answer 28

1) E. coli
2) Enterotoxin
3) V. Cholera
4) C. Diff

Question 29

Which neurotransmitters may induce diarrhea?

Answer 29

1) ACh
2) 5-HT
3) bradykinin

Question 30

Which ion is preferentially lost with diarrhea?

Answer 30

Potassium