GI Physiology

Question 1

Secretin - produced by what cells?

Answer 1

S cells of SI (duod and jejun)

Question 2

Secretin - stimuli (2) and inhibitors (1)

Answer 2

Stimuli: ACID and fat
Inhibitors: somatostatin

Question 3

Gastrin - produced by what cells?

Answer 3

G cells of antrum (also duod and jejun)

Question 4

Gastrin - stimuli (4) and inhibitors (2)

Answer 4

Stimuli: protein, distension, ACH, GRP/bombesin
Inhibitors: acid, somatostatin

Question 5

What is the primary purpose of gastrin?

Answer 5

Incr gastric acid

Question 6

CCK - produced by what cells?

Answer 6

I cells of SI (duod and upper jejun)

Question 7

CCK - stimuli (3) and inhibitors (1)

Answer 7

Stimuli: FAT, acid, protein
Inhibitors: somatostatin

Question 8

What is the primary purpose of CCK?

Answer 8

facilitate digestion, esp of fatty meals

Question 9

Gastric Inhibitory Peptide - produced by what cells?

Answer 9

K cells of duodenum, jejunum

Question 10

Gastric Inhibitory Peptide - stimuli (3) and inhibitors (3)

Answer 10

Stimuli - fat, protein, carbs

Inhibitors - acid, GI stasis, insulin

Question 11

What is the primary purpose of GIP?

Answer 11

stimulate insulin release during hyperglycemia

Question 12

Motilin - produced by what cells?

Answer 12

M cells of duod (also jejunum)

Question 13

Motilin - stimuli (4)

Answer 13

Stimuli - fat, acid, ACH, fasting (growling tummy)

Question 14

Gastrin Releasing Peptide (Bombesin) - action

Answer 14

“on” switch for GI tract

stimulates gastrin release from G cells

Question 15

Motilin - actions

Answer 15

incr gastric and intestinal motility

Question 16

Vasoactive Inhibitory Peptide - actions

Answer 16

relaxes sphincters (pylorus and ileocecal)
incr secretion of water into panc secretions
inhib gastric acid
vasodilation

Question 17

Somatostatin - produced by what cells?

Answer 17

D cells of the SI

Question 18

Somatostatin - stimuli (3) and inhibitors (2)

Answer 18

Stimuli - CCK, acid, gastrin

Inhibitors - ACH, histamine

Question 19

Somatostatin - actions

Answer 19

“off” switch for the GI tract

decrease secretions and GI motility

Question 20

Pancreatic Polypeptide - produced by what cells?

Answer 20

PP cells

Question 21

Pancreatic Polypeptide - stimuli (2)

Answer 21

protein, ACH

Question 22

Pancreatic Polypeptide - action

Answer 22

decr panc secretions

Question 23

What is produced by parietal cells (3)?

Answer 23

HCL, intrinsic factor, leptin

Question 24

3 things that stimulate parietal cell secretions?

Answer 24

histamine, gastrin, ACH

Question 25

1 thing that inhibits parietal cell secretion?

Answer 25

prostaglandins

Question 26

What is produced by chief cells (2)?

Answer 26

pepsinogen, leptin

Question 27

4 things that stimulate chief cell secretions?

Answer 27

ACH, histamine, gastrin, secretin

Question 28

1 thing that inhibits chief cell secretion?

Answer 28

somatostatin

Question 29

What is produced by ECL cells (1)?

Answer 29

histamine

Question 30

4 things that stimulate ECL cells?

Answer 30

catecholamines, ACH, gastrin, CCK

Question 31

1 thing that inhibits ECL cells?

Answer 31

somatostatin

Question 32

what is produced by pancreatic PP cells?

Answer 32

pancreatic polypeptide

Question 33

what is produced by pancreatic delta cells?

Answer 33

somatostatin

Question 34

what is produced by pancreatic alpha cells?

Answer 34

glucagon

Question 35

what is produced by pancreatic epsilon cells?

Answer 35

ghrelin

Question 36

what is produced by pancreatic beta cells (2)?

Answer 36

insulin, amylin

Question 37

Name the 5 layers of the SI wall (outside to inside)

Answer 37

``` serosa longitud sm musc circ sm musc submucosa mucosa ```

Question 38

Location and alternate name of the myenteric plexus?

Answer 38

between the two muscle layers | Auerbach's plexus

Question 39

Actions of the myenteric plexus?

Answer 39

incr GI tone incr peristalsis inhibition of sphincters

Question 40

Location and alternate name of the submucosal plexus?

Answer 40

submucosal | Meissner's plexus

Question 41

Actions of the submucosal plexus?

Answer 41

local secretions local contraction local absorption

Question 42

What is the action of the gastrocolic reflex?

Answer 42

empty the colon

Question 43

What is the action of the enterogastric reflex?

Answer 43

inhibit gastric motility and secretion

Question 44

What is the action of the colonoileal reflex?

Answer 44

keep ileal contents from emptying into colon

Question 45

Name 7 things that are vasodilatory in the GI tract

Answer 45

``` CCK Vasoactive intestinal peptide gastrin secretin kallidin bradykinin adenosine ```

Question 46

Where are the oxyntic glands located?

Answer 46

Stomach - fundus and body

Question 47

Where are the pyloric glands located?

Answer 47

Stomach - pylorus and antrum

Question 48

What are the 4 cell types in the oxyntic glands?

Answer 48

mucus neck cells parietal (oxyntic) cells peptic (chief) cells ECL cells

Question 49

Three stimuli for pancreatic secretions?

Answer 49

ACH, CCK, secretin

Question 50

What are the two cell types in pyloric glands?

Answer 50

mucus cells | G cells

Question 51

Trace the path of protein stimulation leading to acid release in the stomach

Answer 51

Protein stimulates the G cells to release gastrin Gastrin stimulates the ECL cells to release histamine Histamine acts locally in the oxyntic gland to stimulate the parietal cells to release HCL **Gastrin also directly stimulates the parietal cells to release HCL

Question 52

Three enzymes produced by the pancreas that digest proteins

Answer 52

trypsin[ogen] chymotrypsin[ogen] [pro]carboxypolypeptidase

Question 53

Enzyme produced by the pancreas to digest carbs

Answer 53

pancreatic amylase

Question 54

Three enzymes produced by the pancreas to digest fats

Answer 54

pancreatic lipase cholesterol esterase phospholipase

Question 55

three major sources of carbs in the diet

Answer 55

sucrose lactose starches

Question 56

what is lactose broken down into?

Answer 56

galactose and glucose

Question 57

what is sucrose broken down into?

Answer 57

fructose and glucose

Question 58

what is maltose broken down into?

Answer 58

2 glucose molecules

Question 59

What do the G cells of the pyloric glands produce?

Answer 59

gastrin

Question 60

What do the ECL cells of the oxyntic gland produce?

Answer 60

histamine | **these are the ONLY cells that secrete histamine**

Question 61

What do the peptic (chief) cells of the oxyntic gland produce (2)?

Answer 61

pepsinogen, leptin

Question 62

What do the oxyntic (parietal) cells of the oxyntic gland produce (3)?

Answer 62

HCl, intrinsic factor, leptin

Question 63

What are three cell types that regulate parietal cell activity and do they inhibit or stimulate?

Answer 63

ECL cell - produces histamine (stimulates) G cell - produces gastrin (stimulates) D cell - produces somatostatin (inhibits gastrin)

Question 64

What cells produce glucagon?

Answer 64

alpha cells of pancreas | L cells of distal SI, and colon

Question 65

Glucagon - actions?

Answer 65

``` glycogenolysis gluconeogenesis lipolysis ketogenesis GLP-1 enhances insulin release GLP-2 decreases gastric emptying and motility ```

Question 66

Glucagon - stimuli?

Answer 66

hypoglycemia | glucose and lipids in colon

Question 67

Ghrelin - produced by what cells?

Answer 67

endocrine cells in stomach | hypothalamus

Question 68

Ghrelin - 2 effects?

Answer 68

pituitary GH secretion | incr gastric emptying

Question 69

Gastrin Releasing Peptide (Bombesin) - stimulus?

Answer 69

ACH

Question 70

What is the action of secretin on bicarb release?

Answer 70

increases it (pancreas and GB)

Question 71

What is the action of secretin on pepsin?

Answer 71

increases it

Question 72

What is the effect of secretin on gastrin?

Answer 72

decreases it

Question 73

What is the effect of gastrin on pepsinogen?

Answer 73

increases it

Question 74

What is the primary purpose of secretin?

Answer 74

increase secretions from GI tract (esp pancreas)

Question 75

What is the effect of gastrin on pancreatic secretions?

Answer 75

increases them

Question 76

What is the effect of CCK on pancreatic secretions?

Answer 76

increases them

Question 77

What is the effect of CCK on gastric emptying?

Answer 77

decreases it

Question 78

What is the effect of CCK on appetite?

Answer 78

decreases it

Question 79

What is the effect of CCK on the gall bladder?

Answer 79

causes contraction

Question 80

What is the effect of GIP on insulin?

Answer 80

increases it

Question 81

What is the effect of GIP on gastric acid?

Answer 81

decreases it

Question 82

What is the effect of GIP on gastric emptying?

Answer 82

inhibits it