Regulation of acid production and motility

Question 1

What are the 3 different types of GIT control

Answer 1

Autonomic, enteric and hormonal

Question 2

What are the 3 types of Gastric Acid secretion?

Answer 2

Cephalic, Gastric and intestinal phase

Question 3

What does sight, smell and taste trigger?

Answer 3

Cephalic phase - increase HCL

Question 4

What does gastric distension and peptides trigger?

Answer 4

Gastric Phase - increase HCL

Question 5

What does acid in duodenum trigger?

Answer 5

Intestinal phase - feedback inhibition of HCL via secretin

Question 6

What drives gastric acid secretion?

Answer 6

Gastrin, histamine and ACh

Question 7

What inhibits gastric acid secretion?

Answer 7

Somatostatin, secretin and prostaglandins

Question 8

What creates a pressure gradient towards ileo-caecal sphincter?

Answer 8

Pacemaker activity not being the same along the lengthy of the GIT

Question 9

Is the fundus rhythmic?

Answer 9

no

Question 10

How are slow waves generated?

Answer 10

Interstitial cells of Cajel (ICC) - PNS

Question 11

Describe properties of the ICCs?

Answer 11

Gap junctions with smooth muscle
Close to nerve terminals
Postulated to have conductive function
Kit positive

Question 12

What impairs GIT motility?

Answer 12

Blocking Kit with antibodies

Question 13

What is the function of slow waves?

Answer 13

Increase probability of opening for voltage-dependent Ca2+ channels
Increases resting membrane potential

Question 14

What generates these slow waves

Answer 14

ICCs

Question 15

What two things increase the force of contraction in the stomach?

Answer 15

Slow waves + increased membrane polarisation

Question 16

What does gastric distension do?

Answer 16

Accelerates emptying rate

Question 17

What types of food empty faster than others?

Answer 17

Liquids > carbohydrate rich meals > protein rich meals > fatty meals

Question 18

What is the feedback inhibition involved with gastric distension?

Answer 18

Duodenal feedback: negative enterogastric reflex triggered by vagal sensory fibres

Question 19

What do the vagal sensory fibres detect?

Answer 19

pH, osmolality, fatty acids and amino acids

Question 20

What effect do secretin and CCK have on gastric emptying rate?

Answer 20

Decreases it

Question 21

What is a gastro esophageal reflux disease symptom?

Answer 21

Heartburn
Barrett’s esophagus can develop

Question 22

Define vomiting

Answer 22

Rapid removal of potential harmful material

Question 23

What are the 2 phases of vomiting?

Answer 23

Prodromal and expulsive phase

Question 24

What are traits of the prodromal phase?

Answer 24

Nausea, pallor, sweating, salivation and tears

Question 25

What are the traits of the expulsive phase?

Answer 25

Giant retrograde contraction from jejenum
Abdominal wall contraction & glottis closes
Relaxation of LOS/LES
Esophageal shortening – longitudinal muscle
Diagram contracts – crural diaphragm relaxes
(except during retching)