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2.2 GI Hormones, Paracrines, Endocrines and Neurocrines

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heyidika's version from 2018-02-13 19:49

Section 1

 

Neurocrines
Question Answer
Acetylcholine (Ach)s: Cholinergic neurons;
t: Smooth muscle - contraction in GI wall, Salivary glands - increase secretion, stomach - increase secretion, pancreas - increase secretion;
noradrenaline (NA)s: adrenergic neurons;
t: smooth muscle - relaxation in GI wall, salivary glands - increase secretion;
vasoactive intestinal peptide (VIP)s: enteric nervous system;
t: smooth muscle - relaxation in GI wall, pancreas - increase secretion, intestine - increase secretion
Gastrin-releasing Peptide (GRP)/(Bombesin)s: neurons in gastric mucosa, vagal nerve endings
t: G cells in antrum of stomach
a: increase gastrin release
Enkephalins (opiates)s: neurons of the mucosa and smooth muscle
t: smooth muscle - contraction, intestinal secretions - decreases
Neuropeptide Ys: neurons of the mucosa and smooth muscle
t: smooth muscle - relaxation, intestinal secretions - decreases
Substance Ps: co-secreted with Ach
t: smooth muscle - contraction, salivary glands - increase secretion
memorize

Section 2

Hormones
Question Answer
Gastrins: G cells in antrum of stomach;
t: parietal cells in body of stomach;
a: increase H+ secretion, stimulate growth of gastric mucosa
Cholecystokinin (CCK)s: I cells in duodenum and jejenum, neurons in ileum and colon;
t: pancreas, gallbladder;
a: increase enzyme secretion, increase contraction
Secretins: S cells in small intestine;
t: stomach, pancreas
a: decrease gastric acid secretion, increase HCO3- and fluid secretion by pancreatic ducts
Gastric-Inhibitory Peptide (GIP)s: K cells in duodenum and jejenum;
t: pancrease, stomach;
a: exocrine: decrease gastric H+ secretion; endocrine: increase insulin release
Glucagons: alpha cells from pancreatic islet of Langerhans;
t: liver,
a: increase glycogenolysis and gluconeogenesis
Guanylins: ileum and colon;
t: intestine;
a: increase fluid absorption
Motilins: endocrine cells of the upper GI tract;
t: oesophageal sphincter, stomach and duodenum;
a: increases smooth muscle contraction
Neurotensins: N cells of ileum;
t: smooth muscle, vagus;
a: relaxes smooth muscle, decreases gastric acid secretion
memorize

Section 2

Hormones
Question Answer
Gastrins: G cells in antrum of stomach;
t: parietal cells in body of stomach;
a: increase H+ secretion, stimulate growth of gastric mucosa
Cholecystokinin (CCK)s: I cells in duodenum and jejenum, neurons in ileum and colon;
t: pancreas, gallbladder;
a: increase enzyme secretion, increase contraction
Secretins: S cells in small intestine;
t: stomach, pancreas
a: decrease gastric acid secretion, increase HCO3- and fluid secretion by pancreatic ducts
Gastric-Inhibitory Peptide (GIP)s: K cells in duodenum and jejenum;
t: pancrease, stomach;
a: decrease gastrin release, exocrine: increase insulin release, endocrine: decrease fluid absorption
Glucagons: alpha cells from pancreatic islet of Langerhans;
t: liver,
a: increase glycogenolysis and gluconeogenesis
Guanylins: ileum and colon;
t: intestine;
a: increase fluid absorption
Motilins: endocrine cells of the upper GI tract;
t: oesophageal sphincter, stomach and duodenum;
a: increases smooth muscle contraction
Neurotensins: N cells of ileum;
t: smooth muscle, vagus;
a: relaxes smooth muscle, decreases gastric acid secretion
memorize

Section 3

Paracrines

 

Question Answer
Somatostatins: Delta cells in stomach, small intestine and pancreas
t: stomach - decrease gastrin release
small intestine - increase fluid absorption, decrease fluid secretion, increase smooth muscle contractions
pancreas - decrease exocrine and endocrine secretions
liver - decrease bile flow
Histamines: endocrine cells of the gastric mucosa in stomach
t: stomach
a: stimulates gastric acid release from parietal cells in stomach
memorize