Gut Hormones Flashcards

1
Q

What are the two forms of gastrin

A

G34

G17

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2
Q

When is gastrin produced

A

Antrum

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3
Q

When is gastrin released

A

High pH

Stimulated by proteins, peptides and amino acids

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4
Q

What are the two actions of gastrin

A

Acid secretion from parietal cells

Growth promoting effects on gastric mucosa

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5
Q

Hypergastrinaemia occurs in…

A

Decreased acid production (atrophic gastritis)

Overuse of PPI

zollinger ellison syndrome

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6
Q

Which cells secrete CCK and where

A

I cells

Small intestine

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7
Q

CCK release is stimulated by…

A

Ingestion of fat and protein

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8
Q

What are the 3 actions of CCK

A

Gallbladder contraction and bile acid release

Regulates gastric emptying and bowel motility to induce satiety

Regulates meal stimulated pancreatic secretion

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9
Q

Which conditions are associated with a low CCK

A

Coeliac disease

Bulimia

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10
Q

Which condition are CCK levels reportedly high

A

Chronic pancreatitis

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11
Q

Which cells secrete secretin

A

S cells

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12
Q

When is secretion released

A

Stimulated by acid in duodenum

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13
Q

What are the actions of secretin

A

Pancreatic and bicarbonate secretion neutralising acidic chyme in intestine

Inhibits gastric acid, gastric secretions and intestinal motility

Aids osmoregulation of hypothalamus and pituitary

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14
Q

Where is VIP released from

A

Neurones in gut, pancreas

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15
Q

What is the action of VIP

A

Vasodilator = smooth muscle relaxation

Secretion of electrolytes into lumen

Neuromodulator of sphincters of GI tract

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16
Q

What does a lack of VIP lead to?

A

Hirschsprungs

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17
Q

What does excessive VIP lead to

A

WDHA

Watery diarrhoea
Hypokalaemia
Achlorhydria

18
Q

Which cells produce glucagon

A

Alpha cells in pancreas

19
Q

What is the action of glucagon

A

Regulates glucose homeostasis:

Gluconeogenesis
Glycogenolysis
Lipolysis

20
Q

Where is gastric inhibitory polypeptide released

A

K cells in duodenum, jejunum mucosa

21
Q

What is the action of GIP cells

A

Inhibit gastric acid secretion
Stimulate insulin release in hyperglycaemic state

Augments triglyceride storage contributing to fat accumulation

22
Q

Where is pancreatic polypeptide released

A

Endocrine cells of pancreas

23
Q

Describe pancreatic polypeptides actions

A

Self regulation of pancreatic secretory activity

Affects hepatic glycogen levels and GI secretions

24
Q

Somatostatin is produced in the…

A

D cells

25
Q

When is somatostatin released

A

Influenced by pH

Mechanical stimulation

Dietary component (fat, protein, glucose)

26
Q

Actions of somatostatin

A

Regulate gastric acid secretion

Reduce pepsinogen secretion

Inhibit bicarbonate and pancreatic enzyme release

Reduce bile flow

Reduce gut motility

Reduce splanchnic blood flow

27
Q

Lepton blood levels reflect total body fat stores, but where is it released from

A

Chief and adipose cells in stomach

28
Q

How does lepton regulate food ingestion?

A

Lowers neuropeptide Y levels (a potent stimulator of food intake within the brain)

29
Q

Where is ghrelin produced

A

P/D1 cells in gastric fundis, pancreas, pituitary

30
Q

Describe the actions of ghrelin

A

Stimulate gastric contraction

Enhance stomach emptying

Initiation of ingestion

LEVELS HIGH WHEN HUNGRY

31
Q

Where is motilin produced

A

Endocrine cells in duodenum

32
Q

Motilins secretion is periodic and not affected by food ingestion, but what are its actions?

A

Increase migrating myoelectric complex of GI motility

Stimulate pepsin production

Peristalsis in small intestine in preparation for next meal

33
Q

What does substance P primarily mediate?

A

Neurogenic inflammation

34
Q

What is the role of substance P

A

Activate vomiting reflex

Involvement in nociception

High levels of substance P found in UC and Crohn’s

35
Q

In relation to satiety signals, what is the role of CCK

A

Delays gastric emptying

Signals termination of food ingestion

36
Q

In relation to satiety signals what is the role of ghrelin

A

Initiates meal ingestion

Levels rise rapidly before a meal and fall rapidly afterwards

37
Q

In relation to satiety signals what is the role of glucagon like peptide

A

Delays gastric emptying

Increases satiety

38
Q

In relation to satiety signals what is the role of leptin

A

Reduced food intake

Produces greater reduction in body weight

39
Q

In relation to satiety signals what is the role of neuropeptide Y

A

Increases food intake

Increases proportion of food stored as fat

40
Q

In relation to satiety signals what is the role of peptide YY

A

Reduced calorie intake

Inhibits gastric motility

Increases water and electrolyte absorption in colon