GI Gastric Morility And Gastric Acid Secretion

Question 1

What is the stand the starting point for

Answer 1

Digestion of proteins (via pepsin and HCl)

Question 2

What does the stomach do

Answer 2

Mixes the food with gastric secretions to products chyme

Question 3

What is the absorption like in the stomach

Answer 3

Limited amount

Question 4

How much gastric juice is approx prod by stomach a day

Answer 4

2litre/day

Question 5

What are the structural elements that make up the j shaped bag stomach

Answer 5

Fundus
Cardia 
Body 
Rugae
Pylorus
Antrim 
Lesser and greater curvature

Question 6

What so the mixing like in the stomach

Answer 6

Direction of peristaltic move from funds to pylorus forces food to sphincter
If sphincter open this is emptying to duo
If closed retropulsion of chyme allowing mix

Question 7

What determines the escape of chyme through the pyloric sphincter

Answer 7

The strength of the Antral wave

Question 8

What is the strength of the Antral wave governed by

Answer 8

Gastric factors originating in stomach

Duodenal factors originating in duo

Question 9

What are the gastric factors influencing gastric emptying

Answer 9

Rate of emptying proportional to volume of chyme in stomach
- as vol increases the greater distension of wall of stomach

Consistency of chyme
- rotting facilitated by finely divided thick liquid chyme so can fit through pyloric sphincter

Question 10

What are the duodenal factors which influence gastric emptying

Answer 10

Duodenum must be ready to receive chyme and can delay this emptying

Stimuli which duodenum drives the neuronal and hormonal responses

Question 11

How can the duo delay the stomach emptying

Answer 11

Neuronal - enterogastric reflex, when duo senses chyme sends signal to decrease Antral peristalsis via intrinsic nerve plexuses and autonomic neurones

Homonal - release enterogastrones( secretin, cck) from endocrine cells in duo inhibit stomach contraction thoug GPCR’s

Question 12

How does fat influence the duodenal hormonal and neural responses

Answer 12

Potent delay in emptying required for digestion and abs in small intestine
Difficult to digest as insol water
Digested v slow

Question 13

Howes acid affect the duodenal hormonal and neuronal repsonse

Answer 13

Only small mount added

Time required for neutralisation by bicarbonate sec from pancreas

Question 14

How does hyper tonicity affect the hormonal and neuronal factors of the duo

Answer 14

Products of carb and protein digestion are osmotically active and draw water into small intestine
Danger of reduced plasma vol and circulatory disturbances

Question 15

What does a g cell in the gastric pit release

Answer 15

Gastrin

Question 16

What’s does a d cell in a gastric pit release

Answer 16

Somatostatin.

Question 17

What does a parietal cell release

Answer 17

HCl and intrinsic factor

Question 18

What does an enterochromaffinlike cell prod

Answer 18

Histamine

Question 19

What does a chief cell produce

Answer 19

Pepsinogen

Question 20

What are the two oes of gastric pits and where are they found

Answer 20

Pyloric gland area in the Antrum

Oxcyntic mucosa in the fungus and body

Question 21

What fuels are found in the pyloric gland area pastric pit

Answer 21

D cells and g cells

Question 22

What cell homes are found in the oxcyntic mucosa gastric pits

Answer 22

Parietal
Enterochromaffinlike cell
Chief cell

Question 23

What does an oxcyntic gland produce

Answer 23

HCl 
Pepsinogen 
Histamine 
Mucus
Intrinsic factor

Question 24

What does a pyloric area gland produce

Answer 24

Gastrin
Somatostatin
Mucus

Question 25

He hat does HCl from the oxcyntic mucosagastric pit do

Answer 25

Activates pepsinogen to pepsin for proetin digestion Denatures protein breaks tertiary and secondary structures Kills most micor ORGS ingested in food

Question 26

What does pepsinogen from the oxcyntic do

Answer 26

Inactive preserver for pepsin for protein digestion

Question 27

What does intrinsic factor from oxcyntic do

Answer 27

Binds vit b12 allowing abs in terminal ileum only thing essential for life

Question 28

What does the histamine and mucus do form the oxcyntic do

Answer 28

Histamine - stim HCl sec | Mucus - protective pord in gastric pits and epi, stops apical attack of epi cells

Question 29

What does gastrindo form the pyloric do

Answer 29

Stimulate HCl sec

Question 30

What's does somatostatin do form pyloric

Answer 30

inhibits HCl sec between meals | Counter regulation to Gastrin

Question 31

What is the resting state of the parietal cell

Answer 31

Hydrogen and pottasium ATPase largely in cyto tubulovesicles

Question 32

What so the stim state of the parietal cell

Answer 32

Hydrogen and pottasium ATPase traffics to apical mem taking residence in extended Microvilli

Question 33

What are the 3 phases of gastric sec

Answer 33

Cephalic Gastric Intestinal

Question 34

What is the cephalic phase of gastric sec

Answer 34

Before foods reaches stomach, anticipatory phase causes increases parasymp flow to stomach and sec acid to prep for digestion of meal

Question 35

What is the gastric phase of gastric secs

Answer 35

When food is In the stomach

Question 36

What is the intestinal phase of gastric sec

Answer 36

After food left stomach chyme acid sec off | Includes factors from small intestine

Question 37

What does muscarinic receptor antagonists do and an example

Answer 37

Block acid sec competitively

Question 38

What does h2 histamine receptor antagonists do and an example

Answer 38

Block acid sec competitively | Ranitidine

Question 39

What do proton pump inhibitors do and an example

Answer 39

Block acid sec by covalent modification | Omeprazole

Question 40

What do non steroidal anti inflammatory drugs do and an examole

Answer 40

Block acid sec irreversibly | Aspirin

Question 41

What protects the mucosa form HCl attack and pepsin

Answer 41

Locally produced prostaglandins.

Question 42

What do locally produced prostaglandins do

Answer 42

Reduce acid sec Increase mucus and bicarbonate sec Increase mucosal blood flow

Question 43

What is a peptic ulcer

Answer 43

Any ulcer in an area where the mucosa is exposed to HCl and pepsin (stomach, duo)

Question 44

What so th development of a peptic ulcer associated with

Answer 44

A shift in balance between mucosal damaging and mucosal protecting mechanisms

Question 45

What do NSAIDs do

Answer 45

Reduce prostaglandin formations - COX1 Inhibition which may trigger Gastric ulceration Bleeding

Question 46

How can longer term gastric damage due to NSAIDs be treated

Answer 46

With pge1 analogue misoprostol Inhib basal and food stim gastric acid formation Maintains secretion of mucus and bicarbonate Compensates for loss prostaglandins when cox1 inhib

Question 47

What is the origination of a peptic ulcer form

Answer 47

Imp factor H.pylori motile bacteria which burrows into mucosal barrier where it is protected by gel but caused inflammation and breakdown mucosal barrier expo the mucosal mem to HCl and pepsin

Question 48

What do drugs used to treat peptic ulcers aim to do

Answer 48

Decrease acid sec. Increasing mucosl resistance Eradicating h pylori

Question 49

What are drugs used to reduce gastric acid used for

Answer 49

Peptic ulcers Gastric oesophageal reflux disease Acid hypersecrtion

Question 50

What are mechanisms of antisec activity

Answer 50

Inhibition of proton pump Competitive antagonisms if histamine h2 receptors Competion antagonism of muscarinic m1 and m2 ACh receps Antagonism of Gastrin receps

Question 51

What is the stomach driven by (nerve)

Answer 51

Vagus