Gastrointestinal Paracrines and Their Functions

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Questions and Answers

What are the primary paracrines found in the gastrointestinal tract?

Somatostatin and histamine (correct)
Serotonin and dopamine
Adrenaline and norepinephrine
Insulin and glucagon

Histamine decreases gastric $H^+$ secretion in the stomach.

False (B)

What triggers the secretion of somatostatin in the gastrointestinal tract?

H+ in the lumen

Somatostatin inhibits the release of all GI __________.

<p>hormones</p> Signup and view all the answers

Match the paracrine to its action:

<p>Somatostatin = Inhibits gastric $H^+$ secretion Histamine = Increases gastric $H^+$ secretion Vagal stimulation = Inhibits somatostatin secretion</p> Signup and view all the answers

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Study Notes

Paracrines in the Gastrointestinal Tract

Paracrines are signaling molecules released by endocrine cells in the gastrointestinal (GI) mucosa.
They diffuse over short distances to target cells within the GI tract.
Key GI paracrines include somatostatin and histamine.

Somatostatin

Secreted by cells throughout the GI tract in response to hydrogen ions ($H^+$) present in the lumen.
Vagal stimulation inhibits the secretion of somatostatin.
Functions to inhibit the release of all gastrointestinal hormones, effectively regulating digestive processes.
Also inhibits gastric secretion of hydrogen ions ($H^+$), reducing acidity in the stomach.

Histamine

Secreted by mast cells found in the gastric mucosa.
Increases gastric secretion of hydrogen ions ($H^+$) directly.
Enhances the effects of gastrin, a hormone that stimulates gastric acid secretion, and vagal stimulation, promoting digestive function.