Gastro hormones

Question 1

What is the function of the enteric endocrine system?

Answer 1

Secretions
Motility
Appetite

Question 2

Describe the role of gastrin/ where it is produced and the stimuli for its release

Answer 2

Produced: G cells in duodenum and stomach
Stimulated by: Presence of peptides and Aa in gut lumen/ distended stomach/ vagal stimulation/ hypercalcaemia
Role: stimulates release from gastric acid from parietal cells and stimulates release of pepsinogen from chief cells

Question 3

What are the main GI hormones?

Answer 3

• Insulin
• Glucagon
• Gastrin (local)
• Ghrelin
• GIP
• Secretin
• Cholecystokinin (local)

Question 4

At what pH does gastrin secretion stop?

Answer 4

~3

Question 5

What do tumours of the gastrin secreting cells cause?

Answer 5

Stomach ulcers

Question 6

Discuss secretin

Answer 6

• Produced in duodenum
• Stimulated by presence of H+ in small intestine
• Stimulates release of pancreatic juices and bile.

Question 7

Discuss CCK

Answer 7

• Produced in the duodenum
• Stimulated by presence of fatty acids, monoglycerides, Aa in small intestine
• Stimulates release of pancreatic enzymes (lipase) and contraction of the gall bladder (bile)

Question 8

What gastric hormones enables insulin release?

Answer 8

GIP

GLP-1 promotes its secretion and it also suppresses glucagon driven gluconeogenesis

Question 9

Which gastric hormones promotes satiety?

Answer 9

-GLP-1

Question 10

Discuss motilin

Answer 10

Produced in Mo cells of SI
Maintains motility in stomach and SI
Stimulate production of pepsin

Question 11

What hormone causes satiety and which causes appetite?

Answer 11

• Leptin= satiety

- Ghrelin= appetite

Question 12

What does the satiety and appetite centres respond to?

Answer 12

• Satiety= high glucose

- Appetite= Low glucose

Question 13

Why do some Labradors have an endless appetite?

Answer 13

-The Ghrelin that stimulates appetite should block MSH BUT in some Labradors the MSH doesn’t work properly so they have no appetite suppression

Question 14

What is the lipostat hypothesis?

Answer 14

• Adipose tissue produced leptin
• Amount of leptin produced is proportional to amount of fat so if you have more fat then more leptin is produced to should have stronger appetite suppression

Question 15

Give an example of an anorexinergic hormone

Answer 15

Leptin

Question 16

Discuss ghrelin

Answer 16

• Mainly produced in the stomach
• Increases before meals then decreases
• STIMULATES APPETITE

Question 17

Give an examples of an orexigenic hormone

Answer 17

Ghrelin

Question 18

What is the glucostat hypothesis?

Answer 18

That high glucose stimulates the satiety centre

-BUT remember ruminants don’t use much glucose as they use VFAs

Question 19

What is the thermostat hypothesis?

Answer 19

Fall in body temperature causes appetite stimulation