Lecture 36-37- Regulation of GI Function

Question 1

What is the name of the section of the hypothalamus that is the main location for energy control?

Answer 1

Arcuate nucleus

Question 2

What are the two types of neurons within the arcuate nucleus and their function

Answer 2

Orexigenic neurons- induce appetite
Anorexigenic neurons- reduce appetite

Question 3

What stimulates the stomach to send negative feedback to food intake?

Answer 3

Volume (mechanoreceptors)

Question 4

What hormone is released from the stomach to increase appetite?

Answer 4

Ghrelin

Question 5

When are ghrelin levels highest?

Answer 5

Before a meal

Question 6

What medication is a ghrelin agonist?

Answer 6

Entyce

Question 7

Where is Cholecystokinin (CCK) released and what does it do?

Answer 7

Released by the epithelial cells of the small intestine
Short-lived induction of satiety to stop eating the current meal

Question 8

Where is Peptide YY released and what does it do?

Answer 8

Released throughout the intestinal tract, especially distally
Continues satiety several hours after a meal

Question 9

Where is insulin releaased and what does it do?

Answer 9

Released by the pancreas
Supresses appetite while nutrient levels are high

Question 10

Where is leptin released and what does it do?

Answer 10

Released by adipose tissue
Decreases hunger and increases metabolism
Can make it difficult to lose weight

Question 11

What parasympathetic neurons control salivation?

Answer 11

Glossopharyngeal to parotid
Facial to submaxillary and sublingual

Question 12

What is the difference between the saliva of ruminants and nonruminants

Answer 12

Nonruminant saliva has a neutral pH
Ruminants have basic saliva pH to prevent rumen acidosis

Question 13

Is swallowing voluntary or involuntary

Answer 13

Both

Question 14

What are the two phases of swallowing

Answer 14

Oropharyngeal- voluntary
Esophageal- involuntary

Question 15

What is intrinsic nervous system control of the GI tract?

Answer 15

The enteric nervous system

Question 16

Two main enteric nervous system plexuses name and function

Answer 16

Submucosal plexus- near lumen, controls local blood flow
Myenteric plexus- superficial, controls musscle activity

Question 17

Branches that allow enteric neurons to affect multiple target cells at once

Answer 17

Varicosities

Question 18

What do these enteric epithelial cells do
Enterocytes
Goblet cells
Paneth cells
Enteroendocrine cells

Answer 18

Enterocytes- absorb nutrients
Goblet cells- secrete mucous
Paneth cells- secrete antimicrobials
Enteroendocrine cells- secrete hormones

Question 19

What type of cells secrete Secretin

Answer 19

S cells

Question 20

What is the function of secretin?

Answer 20

Regulate pH in the duodenum and promote bile secretion

Question 21

What is the function of Gastrin and what produces it

Answer 21

Produced by G cells in the pylorus duodenum and pancreas
Increases motility and HCl production

Question 22

What produces CCK and what does it do

Answer 22

Produced by epithelial cells in the small intestine and neuronal cells
Increases satiety by slowing digestion triggered by fatty acids/aminoacids

Question 23

What produces Glucose-dependent insulinotropic peptide and what does it do?

Answer 23

Stimulated by glucose in the duodenum
Stimulates insulin secretion

Question 24

What produces motilin and what does it do

Answer 24

Secreted between meals to stimulate fundus contraction/emptying
Stimulated migrating motor complex

Question 25

What neurons are primarily responsible for detecting pathology in the GIsystem

Answer 25

Splanchnic nerves

Question 26

What extrinsic hormone affects the GI system and what does it do

Answer 26

Aldosterone stimulate water and sodium reabsorption from the gut