GI Motility

Question 1

Rhythmic segmentation

Answer 1

• “mixing + churning”

- Circular smooth muscle

Question 2

What cations are the major controls for the BER of the interstitial cells of Cajal

Answer 2

Ca influx leading to depolarization

K+ efflux leading to repolarization

Question 3

Neural path of Oral Glands

Answer 3

Stimulus -> Higher centers -> Salivatory Nucleus of Medulla

-> Otic ganglion -> Parotid
AND
-> Submandicular Ganglion -> Submandicular

Question 4

SMCT1

Answer 4

Short chain fatty acid absorption in the LI

Question 5

Muscular actions in Peristalsis

Answer 5

• Longitudinal muscle contracts distal to bolus widening GI Lumen
• Circular contracts proximal to bolus to propel via inhibition of VIP/NO, ATP

Question 6

Fasting Motility Phases

Answer 6

1. quiescent period
2. irregular activity
3. regular burst of activity

Question 7

Damage to ____ nerve can result in aspiration

Answer 7

Recurrent Laryngeal

Question 8

Gradient from intrathoracic to intra abdominal pressure is ____

Answer 8

12 mmHg

Question 9

Hormones that DEC pressure in LES

Answer 9

Calcitonin gene-related peptide; GIP; Neuropeptide Y; VIP

Question 10

Hormone stimulating emptying

Answer 10

Ghrelin

Question 11

Kinetics of Liquid emptying

Answer 11

1st order kinetics by 12 minutes; Drink 200 ml -> 100 enter duodenum by 12 minutes

Question 12

Normal T1/2 Solid emptying

Answer 12

<2 Hours

Question 13

Pain, Vomiting/ + Acute abdomen

Answer 13

• Pain precedes vomiting in acute surgical abdomen

- Vomiting precedes pain in acute medical abdomen (Bowel Obstruction)

Question 14

GOO

Answer 14

• Gastric Outflow Obstruction

- Non-bilious vomit/emesis

Question 15

Prolonged nausea which precedes vomiting

Answer 15

Distal small or large bowel obstruction

Question 16

Recurrent vomiting of bile-stained fluid

Answer 16

proximal small bowel obstruction

Question 17

Cytotoxic drug-induced Emesis

Answer 17

5HT3 antagonists (Ondansetron)
Central Dopamine antagonist (Netoclopramide)
Cannabinoid receptor antagonist (Dronabinol)
Neurokinin receptor antagonist (Aprepitant)

Question 18

Vestibular Emesis

Answer 18

H1 antagonist (Cyclizine)
Muscarinic antagonist (Scopalamine)

Question 19

What part of the GI tract is composed of striated?Smooth muscle?

Answer 19

Pharynx, Upper 1/2 Esophagus, External Anal Sphincter Striated

All other areas smooth

Question 20

What factors are responsible for tonic contraction of LES between swallows?

Answer 20

Inherent tone in smooth muscle which is augmented by cholinergic nerves

Question 21

What are the major NTs responsible for regulating contraction + relaxation of LES?

Answer 21

• ACh, VIP, NO, ATP