pharmacology of the GI tract

Question 1

how does digestion occur in the mouth and pharynx

Answer 1

mechanical digestion includes chewing and swallowing
chemical digestion of carbohydrates and fats

Question 2

how does digestion occur in the stomach

Answer 2

mechanical digestion includes peristaltic mixing and propulsion
chemical digestion of protein and fats
absorption of lipid soluble substances such as alcohol and aspirin

Question 3

how does digestion occur in the small intestine

Answer 3

mechanical digestion includes mixing and propulsion, primarily by segmentation
chemical digestion of carbohydrates, fats, polypeptides, nucleic acids
absorption of peptides. amino acids, glucose, fructose, fats, water, minerals, vitamins

Question 4

how does digestion occur in the sigmoid colon

Answer 4

mechanical digestion includes propulsion and segmental mixing
no chemical digestion except by bacteria
absorption by ions, water, minerals, vitamins, organic molecules

Question 5

what are the regions of the stomach in order

Answer 5

cardia
fundus
body
antrum
pylorus

Question 6

what are the layers of the stomach

Answer 6

gastric pits - foveloae gastricae
mucosa- gastric glands, muscularis mucosae
submucosa- blood vessels
muscularis- oblique muscle layer, circular muscle layer, longitudinal muscle layer
serosa- connective tissue

Question 7

peristaltic waves in the stomach
what are the three stages

Answer 7

1) propulsion
2) grinding
3) retropulsion

Question 8

propulsion stage meaning

Answer 8

peristaltic waves move from fundus towards the pylorus

Question 9

2 grinding stage meaning

Answer 9

the most vigorous peristalsis and mixing action occurs close to the pylorus. the pyloric end of the stomach acts as a pump that delivers small amounts of chyme into the duodenum

Question 10

retropulsion stage

Answer 10

the peristaltic wave closes the pyloric valve forcing most of the contents of the pylorus back into the stomach

Question 11

in the small intestine how much segmentation and peristalsis occurs

Answer 11

7cm/min segmentation
1cm/min peristalsis movement of chyme

Question 12

what does the oxyntic gland do

Answer 12

surface mucous cell
parietal cell-
mucous neck cell- mucous bicarbonate
enterochromafin like cell- histamine
d cell somatostatin
chief cell pepsinogen
enterochromaffin cell- 5-ht

Question 13

what does pyloric gland

Answer 13

surface mucous cell
mucous neck cell
g cell gastrin
d cell somatostatin
enterochromaffin cell- anp

Question 14

what adrenergic receptor types act on smooth muscle

Answer 14

alpha 1
alpha 2
beta 2

Question 15

what adrenergic receptor types act on sphincters

Answer 15

alpha 2
beta 2

Question 16

what adrenergic receptors type act on glands

Answer 16

no

Question 17

what cholinergic receptor type act on smooth muscle

Answer 17

m 3

Question 18

what cholinergic receptor type act on sphincter

Answer 18

m3

Question 19

what cholinergic receptor type act on glands

Answer 19

m3 m1

Question 20

what is the sympathetic effect on smooth muscle

Answer 20

decreased motility

Question 21

what is the parasympathetic effect on smooth muscle

Answer 21

increased motility

Question 22

what is the sympathetic effect on sphincters

Answer 22

constriction

Question 23

what is the parasympathetic effect on sphincters

Answer 23

dilation

Question 24

what is the sympathetic effect on glands

Answer 24

no effects

Question 25

what is the parasympathetic effect on glands

Answer 25

secretion gastric acid secretion

Question 26

three principles stimulators of acid secretion

Answer 26

acetylcholine ach neurotransmitter gastrin peptide hormone histamine amino acid derivative

Question 27

what are gastric acid related disorders

Answer 27

dyspepsia gastrosesophageal reflux disease GERD peptic ucler zollinger elison syndrome somatostatin

Question 28

what are gastric ulcers

Answer 28

they are in the junction between the antrum and the acid secretory mucosa can happen in the fundus but its rare h pylori infection in 70% of cases gastritis, shallow or deep ulcer inflammatory cells can cause hematemesis or melena vomiting pain starts and aggravated after a meal 1-2 hours (weight loss) high risk of malignancy

Question 29

what are dudodenal ulcers

Answer 29

100% caused by helicobacter pylori most common types of ulcers 95% found in the first part of the duodenum usually small less than 1cm sharply demarcated lesion eosinophils especially on the base of the ulcer can cause melena or hematoschezia pain starts 3-5 hours after the meal pain is relieved by food and increased intensity of the pain at night weight gain

Question 30

what are peptic ulcers

Answer 30

ulcer formed by a balance of tissue damaging chemicals, tissue protective agents, inflammatory causing agents tissue damaging chemicals (peptic enzymes and gastric acid) and tissue protective agents (mucus, bicarbonate secretion, mucosa blood flow,prostaglandin production and epithelial regenerative activity)

Question 31

what can cause peptic ulcers what are the risk factors

Answer 31

Nsaids helicobacter pylori alcohol gastric hyperactivity gastric reflux ischaemia shock delayed gastric emptying

Question 32

what is dyspepsia

Answer 32

indigestion- bloating nausea

Question 33

how do non steroidals cause peptic ulcers nsaids (over the counter)

Answer 33

inhibit prostaglandins in parietal and mucosal cells they will increase production of acid because prostaglandin receptors inhibited and they will decrease bicarbonate prostaglandins act on ep3 receptors on both parietal and mucous cells. on parietal cells, prostaglandins acting ep3 receptors causes inhibition of h+ K+ exchanger however on mucous cells prostaglandins acting on ep3 receptors causes release of bicarbonate which neutralises gastric acid. however nsaids inhibit prostaglandins and so excess secretion of acid and decreased protection from bicarbonate release

Question 34

what are prostaglandin analogues used for

Answer 34

act as a mimic, restore protection of stomach lining as they act as prostaglandins would on ep3 receptors on parietal and mucous cells

Question 35

what is the sympathetic effect on smooth muscle of the gi tract

Answer 35

decreases motility

Question 36

what adrenoceptors are associated with the sympathetic effect of smooth muscle on gi tract

Answer 36

a2 a1 b2

Question 37

what is the sympathetic effect on sphincters of the gi tract

Answer 37

constricts

Question 38

what adrenoceptors are associated wit constriction of the sphincters on gi tract

Answer 38

a2 b2

Question 39

what is the sympathetic effect on glands of the gi tract

Answer 39

no effect

Question 40

what is the parasympathetic effect on smooth muscle of gi tract

Answer 40

increased motility

Question 41

what is parasympathetic effect on sphincters of gi tract

Answer 41

dilatation

Question 42

what is parasympathetic effect on glands of the gi tract

Answer 42

secretion and gastric acid secretion

Question 43

what muscarinic receptors are associated with increased motility of smooth muscle of gi trac

Answer 43

m3

Question 44

what muscarinic receptors are associated with dilatation of sphincters of gi tract

Answer 44

m3

Question 45

what muscarinic receptors are associated with secretion of gastric acid

Answer 45

m3

Question 46

what muscarinic receptors are associated with secretion

Answer 46

m1

Question 47

what are the three principle stimulators of gastric acid secretion

Answer 47

gastrin-peptide hormone histamine-amino acid derivative acetylcholine -neurotransmitter

Question 48

what are the four different histamine receptors for

Answer 48

h1- llergic reactions- increased calcium release gq h2- acid secretion gs increases camp h3- neurotransmitter modulation gi inhibits camp h4- immunomodulator- increases calcium

Question 49

what are the first generation h1 antagonists

Answer 49

dip-hen-hydramine chlor-pheniramine

Question 50

what are the second generation h2 antagonists

Answer 50

loratatidine fexofenadine cetirizine

Question 51

h2 antagonists

Answer 51

cimetidine ranitidine

Question 52

examples of proton pump inhibitors

Answer 52

omeprazole lansoprazole pantoprazole rabeprazole