GIT physiology 2

Question 1

4 regions of the stomach

Answer 1

cardia, fundus, corpus (body), antrum

Question 2

pepsinogen

Answer 2

inactivated pepsin (so it doesn’t digest the secreting cell)

Question 3

3 types of exocrine gland cells in the stomach

Answer 3

mucous neck cells - mucus
parietal cells - intrinsic factor and HCL
chief cells - pepsinogen and gastric lipase

Question 4

2 types of endocrine cells in the stomach

Answer 4

G cell - secretes gastrin

D cell - secretes somatostatin

Question 5

the body is

Answer 5

a reservoir

Question 6

the antrum is

Answer 6

a mixer

Question 7

receptive relaxation

Answer 7

sago-vagal response
relaxes the stomach
triggered by stretch of bolus of food
allows stomach to expand

Question 8

mixing and grinding

Answer 8

closure of the pyloric sphincter

rhythmic waves of muscular activity

Question 9

duodenal distension causes

Answer 9

CCK/secretin secretion
causes the stomach to relax to prevent overloading of the duodenum
pyloric sphincter contracts to prevent regurgitation

Question 10

what controls gastric emptying

Answer 10

feedback from the duodenum

acidity, fat, amino acids, hypertonicity, distension

Question 11

vomiting is stimulated by

Answer 11

irritation
balance
limbic system - emotional
blood chemical

Question 12

mucous neck cells secrete

Answer 12

mucus and bicarbonate

Question 13

mucus secreted in response to

Answer 13

tonic secretion (constant) and irritation of mucosa

Question 14

bicarbonate is for

Answer 14

neutralisation - trapped in the mucosa

Question 15

purpose of mucus

Answer 15

physical barrier between the lumen and the epithelium

Question 16

purpose of bicarbonate

Answer 16

buffers gastric acid to prevent damage to epithelium

Question 17

parietal cells secrete

Answer 17

gastric acid and intrinsic factor

Question 18

gastric acid and intrinsic factor are secreted in response to

Answer 18

acetyl choline, gastrin, histamine

Question 19

purpose of gastric acid

Answer 19

activates pepsin, kills bacteria

Question 20

purpose of intrinsic factor

Answer 20

complexes with vitamin B12 to permit absorption

Question 21

enterochromaffin-like cell secretes

Answer 21

histamine

Question 22

histamine is secreted in response to

Answer 22

acetylcholine, gastrin

Question 23

purpose of histamine

Answer 23

stimulates gastric acid secretion

Question 24

chief cells produce

Answer 24

pepsinogen, gastric lipase

Question 25

pepsin and gastric lipase are secreted in response to

Answer 25

acetylcholine, acid, secretin

Question 26

purpose of pepsin(ogen)

Answer 26

digests proteins

Question 27

purpose of gastric lipase

Answer 27

digests fats

Question 28

D cells secrete

Answer 28

somatostatin

Question 29

somatostatin is secreted in response to

Answer 29

acid in the stomach

Question 30

purpose of somatostatin

Answer 30

inhibits gastric acid secretion

Question 31

G cells secrete

Answer 31

gastrin

Question 32

gastrin secreted in response to

Answer 32

acetylcholine, peptides and amino acids

Question 33

purpose of gastrin

Answer 33

stimulates gastric acid secretion

Question 34

gastric mucosa surface

Answer 34

secretes mucus and HCO3- (acid protection)

Question 35

oxyntic gland area

Answer 35

acid producing body and fundus (proximal 80%) secretes HCl, pepsinogen, IF, mucus

Question 36

pyloric gland area

Answer 36

antrum (distal 20%) produces mucus secrets gastrin (G and D cells)

Question 37

mechanism for acid secretion

Answer 37

maximal in gastric secretions | proton pump which actively transports H+ out in exchange for K+ in

Question 38

proton pumps are located

Answer 38

in the canalicular membrane of the secreting cell, in vessicles in quiescent cell

Question 39

hydrochloric acid produced from

Answer 39

CO2 in the blood being made into carbonic acid

Question 40

for every mole of hydrochloric acid produced

Answer 40

one mole of bicarbonate is produced

Question 41

when inactive proton pumps are

Answer 41

stored in vessicles so they can't be activated

Question 42

to activate proton pumps

Answer 42

vessicles containing them are exocytosed

Question 43

3 hormones activated exocytosing of proton pump containing vesicles

Answer 43

acetylcholine, histamine, gastrin

Question 44

stimulants of gastrin release from G cells

Answer 44

vagal stimulation small proteins and protein digestion products antral distension

Question 45

gastrin release is inhibited by

Answer 45

acid somatostatin blood borne - secretin, GIP, VIP, glucagon, calcitonin

Question 46

roles of gastrin

Answer 46

stimulate acid from parietal cells release histamine from ECL cells release pepsinogen from chief cells

Question 47

D cells

Answer 47

when stomach pH is too low secrete somatostatin to stop gastrin production to stop acid production pH sensitive

Question 48

parietal cells produce

Answer 48

acid

Question 49

mucus gel contains

Answer 49

muffins (glycoproteins) plus trefoil factor (peptides) which stabilise the mucous layer