General Principles

Question 0

Name the GI neurotransmitters. (8)

Answer 0

Acetylcholine (ACh)
Substance P (SP)
Nitric oxide (NO)
Neuropeptide Y
Vasoactive intestinal polypeptide (VIP)
Opioids
Serotonin or 5-hydroxytrptamine (5-HT)
gamma-amino butyric acid (GABA)

Question 1

Name the general layers of the GI tract.

Answer 1

Mucosa
Muscularis mucosae
Submucosal plexus
Circular muscle
Myenteric plexus
Longitudinal muscle

Question 2

Acetylcholine:
Neurons that utilize it. (2)
Effects. (2)

Answer 2

ACh:
Used by parasympathetic and enteric neurons.
Increases motility and secretion.

Question 3

Substance P:
Neurons that utilize it. (2)
Effects. (1)

Answer 3

SP:
Used by parasympathetic and enteric neurons.
Causes muscle relaxation.

Question 4

Nitric oxide:
Neurons that utilize it. (1)
Effects. (3)

Answer 4

NO:
Used by sympathetic neurons.
Decreases motility, blood flow and secretion.

Question 5

Neuropeptide Y:
Neurons that utilize it. (2)
Effects. (2)

Answer 5

Neuropeptide Y:
Used by sympathetic and enteric neurons.
Decreases motility and secretion.

Question 6

Vasoactive intestinal polypeptide:
Neurons that utilize it. (1)
Effects. (2)

Answer 6

VIP:
Used by enteric neurons.
Causes muscle relaxation and increased secretion.

Question 7

Opioids:
What they are. (2)
Effects. (2)

Answer 7

Opioids:
Met and Leu enkephalins.
Decreases motility and secretion.

Question 8

Serotonin:
Neurons that utilize it. (1)
General effect. (1)

Answer 8

Serotonin:
Used by enteric neurons.
Excitatory stimulus.

Question 9

GABA:
Neurons that utilize it. (1)
General effect. (1)

Answer 9

GABA:
Used by enteric neurons.
Inhibitory stimulus.

Question 10

Name the GI hormones. (6)

Answer 10

Cholecytokinin (CCK)
Gastrin
Secretin
Glucose-dependent insulinotropic polypeptide (GIP)
Motilin
Ghrelin

Question 11

General effects of CCK:
Increases. (2 via CCK A-type receptor, 1 indirectly)
Decreases. (1 via CCK B-type receptor)

Answer 11

CCK:
Increases pancreatic enzyme secretion and gallbladder contraction via A receptor.
Increases Sphincter of Oddi tone indirectly.
Decreases gastric emptying via B receptors.

Question 12

General effects of gastrin:

Increases. (3 via CCK B-type receptors)

Answer 12

Gastrin:

Increases gastric acid secretion, motility and mucosal growth.

Question 13

General effects of secretin:
Increases. (1)
Decreases. (1)

Answer 13

Secretin:
Increases pancreatic and biliary bicarbonate secretion.
Decreases gastric acid secretion.

Question 14

General effects of GIP:

Increases. (1)

Answer 14

GIP:

Increases pancreatic insulin secretion via incretin effect.

Question 15

General effects of motilin:

Increases. (1)

Answer 15

Motilin:

Increases GI motility.

Question 16

General effects of ghrelin:

Increases. (3)

Answer 16

Ghrelin:

Increases growth hormone secretion, feeding and weight gain.

Question 17

Name the paracrine signaling molecules of the GI tract. (5)

Answer 17

Histamine
Somatostatin
Prostaglandins
Serotonin
Adenosine

Question 18

General effect of histamine. (1)

Answer 18

Histamine:

Increases gastric acid secretion.

Question 19

General effects of somatostatin. (2)

Answer 19

Somatostatin:

Inhibits motility and secretion.

Question 20

General effect of prostaglandins. (1)

Answer 20

Prostaglandins:

Stimulate secretion of ions.

Question 21

General effect of serotonin. (2)

Answer 21

Serotonin:

Stimulates sensory and secretomotor neurons.

Question 22

General effect of adenosine. (2)

Answer 22

Adenosine:

Alterations in sensory neuron activity and changes in blood flow.