GI Hormones Flashcards

1
Q

Where are gut endocrine cells found? Germ layer derivation?

A

Crypts in the GI tract epithelium

Endodermal

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2
Q

What pole do gut endocrine cells secrete hormones?

A

Basal

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3
Q

Gut endocrine cells are distinguished by not having microvilli true or false?

A

False - they do have microvilli, they are distinguished by being paler than other cells

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4
Q

Gut hormones are what type?

A

Peptide

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5
Q

Which cells secrete histamine in the gut?

A

Enterochromaffin-like cells

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6
Q

Actions of histamine in the gut?

A

Stimulate gastric acid (HCl) secretion via H2 receptors on oxyntic cells

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7
Q

What causes histamine release by ECL cells?

A

Vagal stimulation, stretch or gastrin

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8
Q

Actions of gastrin (+ broad mechanism)

A

Gq coupled — PKC induces insertion of K/H ATP-ase into apical membrane of oxynitic cells
— gastric acid secretion (HCl)

Pepsin secretion

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9
Q

What cells release gastrin?

A

G cells

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10
Q

Stimulation of gastrin release from G cells?

What inhibits gastrin release?

A

Stimulates:

Amino acids
Vagus stimulation
Distension of stomach
Hypercalcaemia

Inhibits:

Low pH (negative feedback)
Somatostatin
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11
Q

Which cells secrete secretin?

A

S cells

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12
Q

Where are S cells found?

A

Duodenum to ileum

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13
Q

What stimulates secretin release? Inhibits?

A

Acid in proximal duodenal lumen

Somatostatin

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14
Q

What are the actions of secretin?

A

Gs coupled PKA activates CFTR and Cl/HCO3 exchanger

Stimulates pancreatic and liver HCO3- secretion and water

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15
Q

Which cells secrete CCK and where are they located?

A

I cells in duodenum and jejunum

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16
Q

What stimulates the release of CCK?

A

Protein, fat digestion products

17
Q

Actions of CCK?

A

Stimulates secretion of pancreatic enzymes and gallbladder contraction
AND suppresses appetite