Week 2: Gastric Motility

Question 1

Functions of the stomach

4 listed

Answer 1

Question 2

size of bolus ejected into the duodenum

Answer 2

1 mm^3

Question 3

General divisions of the stomach

Answer 3

Question 4

Gastric musculature external

Answer 4

Question 5

Internal gastric musculature

Answer 5

Question 6

Receiving and storage functions of the stomach

Answer 6

top of the stomach opens before the bolus arrives which allows liquids or other fast dropping boli to enter the stomach before the peristaltic wave arrives

Question 7

Question

Answer 7

C. VIP/ATP/NO Release from myenteric neurons

Question 8

Receptive relaxation of the fundus and body

Answer 8

Question 9

Recovery of the stomach

Answer 9

Question 10

Mixing and propulsion functions of the stomach: Peristaltic contractions

Answer 10

Question 11

Mixing and propulsion functions of the stomach: Gastric pacemakers

Answer 11

Question 12

Describe electrical slow waves

Answer 12

amplitude and duration dictate how much calcium can enter cells

Question 13

Describe the relationship of electrical slow waves to smooth muscle contraction

Answer 13

Question 14

Describe the gradient of gastric slow waves

Answer 14

The higher in the stomach doesn’t really have slow waves but as you get lower the slow waves get stronger and more spikey which is due to greater Ca2+ influx

Question 15

What drives slow waves

Answer 15

Interstitial cells of Cajal

Question 16

ICCs AKA

Answer 16

Interstitial cells of Cajal

Question 17

Describe interstitial cells of Cajal

Answer 17

Question 18

Most gastric tumors arise from what cell type?

Answer 18

Interstitial Cells of Cajal

Question 19

What happens if interstitial cells of Cajal are knocked out

Answer 19

still have electric potential but no slow waves and animals have difficulty thriving

Question 20

Where do peristaltic contractions originate in the stomach

Answer 20

Question 21

Describe retropulsion

Answer 21

Question 22

Describe retropulsion II

Question 23

Describe the regulation of gastric emptying

Answer 23

Question 24

What mechanisms underlie inhibition of emptying?

Answer 24

Especially in response to fat

Question 25

Describe gastric factors that promote emptying

Answer 25

Question 26

What is the migrating motor complex?

Answer 26

robust coordinated contractions to sweep out residue in the stomach

Question 27

How often does MMC occur?

Answer 27

every ~90 minutes or so

Question 28

Classes of disorders of gastric emptying

Answer 28

* Gastroparesis * Dumping syndrome

Question 29

Gastroparesis causes

Answer 29

* Tumors * ulcers * Vagal nerve damage

Question 30

How does a tumor or ulcer lead to gastroparesis

Answer 30

physical obstruction contributes to pyloric resistance

Question 31

How does vagal nerve damage lead to gastroparesis?

Answer 31

Loss of vagal coordination limits pyloric opening

Question 32

Causes of vagal nerve damage that can lead to gastroparesis

Answer 32

* diabetes * surgical vagotomy for ulcer

Question 33

Symptoms of gastroparesis due to vagal nerve damage

Answer 33

bloating nausea reflux loss of appetite

Question 34

Treatments of gastroparesis due to vagal nerve damage

Answer 34

* Diet modification * Drugs * Surgical treatment to reduce the tone of the pylorus

Question 35

Dumping syndrome is what?

Answer 35

Rapid emptying

Question 36

Complications of Dumping syndrome

Answer 36

An Excessive osmotic load presented to small intestine -\> excessive insulin release -\> hypoglycemia

Question 37

Dumping syndrome is associated with?

Answer 37

Gastric bypass surgery

Question 38

Treatments of Dumping syndrome

Answer 38

* Diet modifications * surgery

Question 39

Summary of gastric motility

Answer 39