Regulation of GI Function II

Question 1

The active hormone gastrin is generated from a

Answer 1

Prepropeptide

Question 2

What are the two major forms of Gastrin?

Answer 2

G-34 (10%)

G-17 (85%)

Question 3

The terminal 4-aa sequence of Gastrin has

Answer 3

Biological activity

Question 4

Which two receptors have over 50% sequence homology?

Answer 4

CCK-1 and CCK-2

Question 5

Has a 1000-fold affinity for CCK

Answer 5

CCK-1

Question 6

Has a high affinity for both CCK and Gastrin

Answer 6

CCK-2/gastrin receptor

Question 7

Regulates gastric acid secretion both directly and indirectly

Answer 7

Gastrin

Question 8

Gastrin DIRECTLY stimulates gastric acid secretion by acting directly on

Answer 8

Parietal cells via CCK-2 receptors

Question 9

Acts indirectly via enterochromaffin-like (ECL) cell mediated histamine release to stimulate parietal cells

Answer 9

Gastrin

Question 10

Gastrin acts indirectly to stimulate parietal cells via

Answer 10

Enterochromaffin-like (ECL) cell-mediated histamine release

Question 11

Vagal activation stimulates multiple responses to regulate

Answer 11

Acid secretion

Question 12

Stimulates gastric motility, helping to propel the food bolus distally

Answer 12

Gastrin

Question 13

Also stimulates mucosal proliferation

Answer 13

Gastrin

Question 14

Due to gastrin stimulation, we see an increase in ECL number resulting in

Answer 14

ECL hyperplasia

Question 15

Gastrin stimulates mucosal proliferation and this increases the number of

Answer 15

Parietal cells

Question 16

What three things stimulate Gastrin secretion?

Answer 16

1. ) Meals (proteins, peptides, AAs)
2. ) High Gastric pH
3. ) Vagal stimulation

Question 17

What are the two types of vagal stimulation that stimulate gastrin release?

Answer 17

Gastrin-releasing peptide and Gastric distension

Question 18

What are the 4 factors that inhibit gastrin release?

Answer 18

1. ) Fasting
2. ) Low gastric pH
3. ) SOMATOSTATIN
4. ) CCK

Question 19

We can see dilation of gastric glands and elongated parietal cells as the result of

Answer 19

Long-standing PPI use

Question 20

Has molecular forms that range in size from 4-83 amino acids

Answer 20

Cholescystokinin (CCK)

Question 21

The predominant molecular form of CCK is

Answer 21

CCK-58

Question 22

Concentrated in the proximal small intestine (and brain)

-Responsible for CCK secretion

Answer 22

I cells

Question 23

CCK is mostly distributed and secreted in the

Answer 23

Duodenum and Jejunum

Question 24

Gastrin is mostly distributed and released in the

Answer 24

Pyloric antrum (and some duodenum)

Question 25

Extend neuropods that allow paracrine and neurocrine actions

Answer 25

CCK

Question 26

What are the two main biologic actions of CCK?

Answer 26

1. ) Stimulates gallbladder contraction | 2. ) Relaxes sphincter of Oddi

Question 27

Stimulates pancreatic enzyme secretion

Answer 27

CCK

Question 28

Delays gastric emptying and inhibits gastric secretion

Answer 28

CCK

Question 29

CCK inhibits the rate and force of

Answer 29

SMC contraction

Question 30

By delaying gastric emptying, CCK contributes to the feeling of

Answer 30

Satiety

Question 31

Found in the duodenum and jejunum (and brain)

Answer 31

Secretin (or S-cells)

Question 32

S-cells are classified as

Answer 32

pH sensors

Question 33

Granule contents are released from the basolateral surface of

Answer 33

S cells

Question 34

Secretin has a half life of

Answer 34

2-3 minutes

Question 35

Secretin is distributed and released in the

Answer 35

Duodenum, Jejunum, and Ileum

Question 36

Stimulates bicarbonate production

Answer 36

Secretin

Question 37

Secretin stimulates bicarbonate production by the

Answer 37

Pancreatic duct cells, cholangiocytes, and Brunner's glands in the duodenum

Question 38

What are the three effects of secretin on the stomach

Answer 38

1. ) Reduces acid secretion 2. ) Slows gastric emptying 3. ) Inhibits gastrin secretion

Question 39

Secretin increases cAMP to activate

Answer 39

PKA

Question 40

What is the main function of secretin from an ion standpoint?

Answer 40

Increases conductance of the CFTR channel leading to outflow of chloride

Question 41

What regulates secretin secretion?

Answer 41

Acid

Question 42

Acidification of the duodenal lumen causes which two things?

Answer 42

1. ) Secretin release into the plasma | 2. ) Pancreatic HCO3- secretion is increased

Question 43

Secretin levels can also be increased by

Answer 43

Fatty Acids

Question 44

There is increased bicarbonate-rich secretion by

Answer 44

Cholangiocytes

Question 45

What are the two major forms of somatostatin?

Answer 45

S-28 and S-14

Question 46

Secrete somatostatin -closely coupled to target cells

Answer 46

D Cells

Question 47

Functions to decrease acid and pepsinogen secretion

Answer 47

Somatostatin

Question 48

Somatostatin also decreases

Answer 48

Pancreatic and small intestine secretion as well as gall bladder contraction

Question 49

The most important hormone during the interdigestive period -sets it apart from other hormones

Answer 49

Motilin

Question 50

Motilin is released cyclically during

Answer 50

Fasting

Question 51

Motilin has a PRO-kinetic effect. I.e. it enhances

Answer 51

Bowel motility

Question 52

Enhances phase 3 contractions

Answer 52

Motilin

Question 53

Produced in the stomach and duodenum where it stimulates gastric contraction and enhances stomach emptying

Answer 53

Ghrelin

Question 54

Ghrelin stimulates appetite and promotes

Answer 54

Weight gain

Question 55

Serotonin (5-HT) is released by

Answer 55

EC cells

Question 56

Functions to initiate peristaltic and segmentation activity in the small intestine

Answer 56

Serotonin

Question 57

Seratonin functions in neural-mediated secretion of

Answer 57

Chloride and Bicarbonate

Question 58

Functions in vasodilation

Answer 58

Seratonin

Question 59

Tryptophan metabolism regulates

Answer 59

Seratonin