GI Tract

Question 1

Gastrin has two forms

Answer 1

17aa (little gastrin), response to eating

34aa (big gastrin), response inbetween meals secreted by low basal levels

Question 2

What is gastrin secreted by

Answer 2

G cells in the Antrum of the stomach

Question 3

What does gastrin do?

Answer 3

Increases hydrogen ion secretion by gastric parietal cells which lowers stomach ph then activates pepsinogen secreted by chief cells

Question 4

Can the vagus nerve stimulate gastrin release

Answer 4

YES

Question 5

Gastrin is inhibited by

Answer 5

Somatostain and low stomach ph

Question 6

What is Zollinger-Ellison syndrome

Answer 6

Gastrin secreting tumor (gastrinoma)

Frequently occurs in pancreas non B cell

Results in atrophy of Gastric mucosa

Question 7

How to treat Zollinger-Ellison syndrome

Answer 7

H2 respect or blockers
Inhibitor of the H+ pump
Removal of the tumor

Question 8

What does CCK do

Answer 8

Coordinates and promotes fat digestion and absorption

33aa structurally related to gastrin

Question 9

What two receptors bind CCK

Answer 9

CCKA- only bind CCK

CCKB- both CCK and gastrin

Question 10

What is secreted by I cells of the duodenal and jejunal mucosa

Answer 10

CCK

But not in response to triglycerides

Question 11

What kind of a meal would stimulate CCK

Answer 11

Fat and protein

Question 12

What are the 5 functions of CCK

Answer 12

1. Contraction of gallbladder
2. Secretion of pancreatic enzymes
3. Secretion of Bicarbonate from pancreaus
4. Trophic effect on exocrine pancreas and gallbladder
5. Inhibition of gastric emptying

Question 13

What is secretin

Answer 13

27 a.a. Peptide similar to glucagon structure

Is a alpha helix

Question 14

What is secreted by S cells of the duodenum in response to increased ph aka H+

Answer 14

Secretin

Question 15

What does secretin do

Answer 15

Inhibits the effects of gastrin on parietal cells

Helps neutralize the ph

Question 16

GIP is secreted by what kind of cells

Answer 16

K cells in the duodenal/jejunal mucosa

Question 17

GIP is in response to All three nutrients major effect is

Answer 17

Stimulation of insulin

It inhibits gastric H+ secretion in animals not humans

Question 18

True or False

Oral glucose greater effect than IV glucose due to oral stimulation of insulin and GIP

Answer 18

True

Question 19

Motilin is secreted when people are

Answer 19

Fasting

Member of gastrin-CCK family

Question 20

Motilin is secreted by

Answer 20

Upper duodenum

Clears the stomach and intestine for preparation of next meal

Question 21

Motilin stimulates

Answer 21

Enzyme production of stomach and pancreas

contraction of gall bladder

Question 22

Ghrelin is secreted by what

Answer 22

Stomach mucosa inbetween eating

Question 23

What does ghrelin do

Answer 23

Increases gastric acid, motility, emptying

May have role in regulating food intake

Increases feelings of hunger

Question 24

What does PP do?

Answer 24

Inhibits pancreatic secretion of bicarbonate and enzymes

Increase after a protein meal

Question 25

How PP decreased

Answer 25

Somatostatin and intravenous glucose

Question 26

GLP are secreted by

Answer 26

L cells in intestinal mucosa

Question 27

L cells are the

Answer 27

Most abundant peptide producing cells in GI tract Unresponsive to plasma levels

Question 28

FLP increase liver

Answer 28

Glycogenolysis and gluconeogensis

Question 29

What has no effect on insulin secretion GLP-1 or 2

Answer 29

GLP2

Question 30

GLP-1 along with peptide YY do what to the stomach

Answer 30

Decrease acid, motility and emptying INCREASES nutrient uptake

Question 31

Paracrines are produced by

Answer 31

GI endocrine cells and act locally

Question 32

What are the two paracrines

Answer 32

Somatostatin Histamine

Question 33

Somatostatin is secreted by

Answer 33

D cells of astral cells in response to low ph Inhibits secretion of GI hormones Secreted also by B cells of pancreas

Question 34

Histamine is produced by

Answer 34

Enteroendocrine cells in GI mucosa especially in stomach near parietal cells Work synergistically with gastrin