Lecture 9 - Stomach Function (Part I)

Question 1

Major Functions of the stomach?

Answer 1

reservoir for food, digests food, controls passage of food into small intestine, gsstric acid secretion, other secretions

Question 2

Antrum function?

Answer 2

Mixes and grinds food

Question 3

Pylorus function?

Answer 3

Regulates size of particles and controls passage of chyme into small intestine

Question 4

4 steps of gastric motility?

Answer 4

Vagovagal reflex (relaxation of fundus), contraction of body and atrum, contraction of pylorus, mixing by retropulsion

Question 5

Dumping Syndrome?

Answer 5

Post-gastric surgery, food moves too quickly and undigested into duodenum, resulting in hyperosmotic chyme causing diarrhoea and rapid fluid shift into gut causing painful intestinal distension

Question 6

Delayed Gastric Emptying e.g.?

Answer 6

Diabetic gastroparesis due to autonomic neuropathy

Question 7

Bacteria present in some stomachs?

Answer 7

H.pylori

Question 8

Gastric Acid aids in the absorption of?

Answer 8

B12 and iron

Question 9

Proton pump action?

Answer 9

ATP binds, proton out, K+ in, CO2 within cell becomes HCO3- into bloodstream (exchanged for Cl-)

Question 10

Protective factors from stomach acid?

Answer 10

Mucus layer, bicarbonate ions

Question 11

Cells of stomach and location?

Answer 11

Parietal and ECL cells (Body); G an D cells (Antrum)

Question 12

ECL Cell function?

Answer 12

Secretes histamine, paracrine activity stimulating acid secretion in neighboring parietal cells

Question 13

G Cell function?

Answer 13

Endocrine, ecretes hormone gastrin into blood stream, activates ECL cells to release histamine

Question 14

D Cell function?

Answer 14

Paracrine and endocrine, H+ increase stimuled, releases somatostatin to bloodstream and neighboring G cells inhibiting gastrin release

Question 15

Ach Released from?

Answer 15

Vagus nerve and enteric neruons

Question 16

Ach stimulation activity?

Answer 16

Parietal cells, ECL cells, G cells

Question 17

Abnormally increased gastric acid secretion?

Answer 17

Gastronima - tumours producing gastrin

Question 18

Pernicious anaemia?

Answer 18

Antibdies against parietal cells

Question 19

Gastric Surgery?

Answer 19

Removal of parts of stomach w cells involved in secretion

Question 20

Vagotomy?

Answer 20

Loss of vegus nerve, therefore Ach

Question 21

Drug effect on reducing acid secretion?

Answer 21

Block proton pump or histamine receptors on parietal cells

Question 22

Prostaglandin function?

Answer 22

protection and repair of gastric mucosa

Question 23

Cephalic Phase?

Answer 23

Smell of food activates Ach release from vagus and enteric nerves stimulation 3 cells

Question 24

Gastric Phase?

Answer 24

Positive feedback: Amino acids released from food stimulate G cells, gastric distension stimulates enteric neurons to release Ach

Question 25

Intestinal Phase: Stomach?

Answer 25

Low pH stimulates somatostatin release from D cells

Question 26

Intestinal Phase: Duodenum?

Answer 26

Fat stimulates Cholecystokinin release, HCl simulates Secretin release

Question 27

Secretin Function?

Answer 27

inhibit gastric emptying and acid secretion, stimulate bicarbonate release from pancreas and bile duct

Question 28

Cholecystokinin Function?

Answer 28

stimulates release of pancreatic enzymes and gallbladder contraction to release bile