Exam 2: GI Tract

Question 1

Largest and most complex endocrine organ

Answer 1

GI tract

Question 2

Percentage of cells of GI tract that secrete hormones

Answer 2

1%

Question 3

Enteroendocrine cells interact extensively w/

Answer 3

ANS and ENS

Question 4

GI tract is a ___ organ

Answer 4

Sensory

Question 5

Gut NT

Answer 5

Catecholamines
ACh
Peptides

Question 6

Peptides from neutrons and gut can act as

Answer 6

NT
Neurohormones
Neuromodulators

Question 7

Vagus supplies para innervation to

Answer 7

Esophagus
Stomach
SI
Prox colon

Question 8

Remainder of colon and rectum receive para supply from

Answer 8

Pelvic N from sacral cord levels

Question 9

Hormonal stim of vagal afferents communicate w/ ____ w/out having to cross

Answer 9

Brain stem; BBB

Question 10

2 forms of gastrin

Answer 10

Little — response to eating

Big — low levels btw meals

Question 11

Gastrin is secreted by

Answer 11

G cells in antrum of stomach

Question 12

Functions of gastrin

Answer 12

Promote H+ secretion — lowers pH — activates pepsinogen

Starts protein digestion

Question 13

Stimuli of gastrin secretion

Answer 13

Products of protein digestion
Distention of stomach
Stim of vagus

Question 14

Gastrin is inhibited by

Answer 14

Somatostatin

Low stomach pH

Question 15

Excess gastrin causes

Answer 15

Inc H+ ion secretion

Hypertrophy of gastric mucosa

Question 16

Deficiency of gastrin

Answer 16

Dec H+ secretion

Atrophy of gastric mucosa

Question 17

Zollinger-Ellison syndrome

Answer 17

Gastrin secretion tumor “gastrinoma”

Question 18

Gastrinoma frequently found in

Answer 18

Pancreas

Question 19

Gastrinoma causes

Answer 19

Inc H+ secretion
Hypertrophy of stomach mucosa
Duodenal ulcers
Acidification of intestinal lumen

Question 20

Treatment of Zollinger-Ellison syndrome

Answer 20

H2 receptor blockers
H+ pump inhibitors
Remove tumor

Question 21

CCK coordinates and promotes

Answer 21

Fat digestion and absorption

Question 22

CCK has some

Answer 22

Gastrin activity

Question 23

CCK secreted by

Answer 23

I cells of duodenal and jejunal mucosa

Question 24

CCK secreted in response to

Answer 24

MG and FA (NOT TGs)

Small peptides and AA

Question 25

A meal containing ______ will stim release of CCK

Answer 25

Fat and protein

Question 26

5 major actions of CCK

Answer 26

1. Contract gallbladder 2. Secrete pancreatic enzymes 3. Secrete HCO3 from pancreas 4. Tropic effect on pancreas and gall 5. Inhibit gastric emptying

Question 27

Purpose of CCK contracting gallbladder

Answer 27

Ejects bile into lumen of SI Bile emulsifies and solubilizes dietary lipids

Question 28

Pancreatic enzymes secreted in response to CCK

Answer 28

Lipases Proteases Amylase

Question 29

Purpose of inhibiting gastric emptying

Answer 29

Enhances fat digestion/absorption

Question 30

Secretin 50% homologous to

Answer 30

Glucagon

Question 31

Tertiary structure of secretin

Answer 31

Alpha helix

Question 32

Secretin is secreted by ___ in response to

Answer 32

S cells in duodenum; H+ and FA in SI

Question 33

Secretin promotes

Answer 33

Secretion of pancreatic and biliary HCO3

Question 34

Purpose of HCO3 secretion

Answer 34

Neutralize H+ in lumen of SI Essential for fat digestion

Question 35

Secretin inhibits effects of

Answer 35

Gastrin

Question 36

GIP is secreted by

Answer 36

K cells in duodenal/jejunal mucosa

Question 37

Major effect of GIP

Answer 37

Stim of insulin

Question 38

GIP inhibits

Answer 38

Gastric H+ secretion (animals)

Question 39

GIP secreted in response to

Answer 39

All 3 types of nutrients

Question 40

Motilin is secreted from

Answer 40

Upper duodenum during fasting

Question 41

Motilin is responsible for

Answer 41

Migrating motility complex

Question 42

Motilin stimulates

Answer 42

Enzyme secretion by stomach and pancreas Contraction of gallbladder

Question 43

GLP secreted by

Answer 43

L cells in intestinal mucosa

Question 44

GLP effects on liver

Answer 44

Inc glycogenolysis and GNG

Question 45

GLP-1 inhibits

Answer 45

``` Glucagon secretion Food intake Patietal cells (dec H+) ```

Question 46

GLP-1 stimulates

Answer 46

Insulin secretion | D cells — secrete somatostatin

Question 47

GLP-1 slows

Answer 47

Gastric emptying

Question 48

GLP-2 trophic effect on

Answer 48

Intestinal mucosa — proliferation — inc surface area for absorption

Question 49

GLP-2 has no effects on

Answer 49

Insulin secretion

Question 50

GLP-2 decreases

Answer 50

Inflamm responses to bowel injury

Question 51

Ileal brake mechanism

Answer 51

Slow gastric/pancreas secretion, stomach emptying and intestinal motility

Question 52

GLP-1 and peptide YY feeds back on stomach in order to

Answer 52

Inc nutrient absorption

Question 53

Paracrine hormones in GI tract

Answer 53

Somatostatin | Histamine

Question 54

Histamine works synergistically with

Answer 54

Gastrin and ACh to stimulate H+ secretion

Question 55

ACh neurocrine actions

Answer 55

Contract smooth ms Inc saliva Inc gastric secretion Inc pancreatic secretion

Question 56

NE neurocrine actions

Answer 56

Relax smooth ms Contract sphincters Inc saliva

Question 57

VIP neurocrine actions

Answer 57

Relax smooth ms Inc intestinal secretion Inc pancreatic secretion

Question 58

GRP neurocrine action

Answer 58

Inc gastrin secretion

Question 59

Enkephalins neurocrine actions

Answer 59

Contract smooth ms | Dec intestinal secretion

Question 60

Neuropeptide Y neurocrine actions

Answer 60

Relax smooth ms | Dec intestinal secretion

Question 61

Substance P neurocrine actions

Answer 61

Contract smooth ms | Inc salivary secretion

Question 62

Para neurocrines

Answer 62

``` ACh VIP GRP Enkephalins Substance P ```

Question 63

Sym neurocrines

Answer 63

NE Enkephalins Neuropeptide Y