GI regulatory substances Flashcards Preview

DEMS details, exam 1 > GI regulatory substances > Flashcards

Flashcards in GI regulatory substances Deck (11)
Loading flashcards...
1

Cholecystokinin (CCK)

Source: I cells (duodenum, jejunum)

Action: Increases pancreatic secretion and gallbladder contraction. Decreases gastric emptying

Regulation: Increased by fatty acids and amino acids

Notes: CCK acts on neural muscarinic pathways to cause pancreatic secretion

2

Gastrin

Source: G cells (antrum of stomach)

Action: Increases gastric H+ secretion, growth of gastric mucosa, increases gastric motility

Regulation: Increased by stomach distention/alkalinization, amino acids, peptides, vagal simulation. Decreased by stomach pH

3

GIP

Source: K cells (duodenum, jejunum)

Action: Decreases H+ secretion

Regulation: Increased by fatty acids, amino acids, oral glucose

4

Motilin

Source: Small intestine

Action: Produces migrating motor complexes

Regulation: Increased in fasting state

Notes: Motilin receptor agonists (eg erythromycin) are used to stimulate intestional peristalsis

5

Secretion

Source: S cells (duodenum)

Action: Increases pancreatic HCO3- secretion, Increases bile secretion, decreases gastric acid secretion

Regulation:

6

Somatostatin

Source: D cells )pancreatic islets, GI mucosa)

Action: Decreases: gastric acid and pepsinogen, pancreatic and small intestine fluid secretion, gall bladder contraction

Regulation: Increased by acid. Decreased by vagal stimulation

Notes: Inhibitory hormone. Antigrowth hormone effects (inhibits digestion and absorption)

7

Nitric Oxide

Source:

Action: Increases smooth muscle relaxation, including LES

Regulation:

Notes: loss of NO secretion is implicated in increased LES tone of achalasia

8

Intrinsic factor

Source: Parietal cells (stomach)

Action: Vitamin B12 binding protein

Regulation:

Notes: Autoimmune destruction of parietal cells can lead to chronic gastritis and pernicious anemia

9

Gastric acid

Source: Parietal cells (stomach)

Action: Decreases stomach pH

Regulation: Increased by histamine, ACh, and gastrin. Decreased by somatostatin, GIP, prostaglandin, secretion

10

Pepsin

Source: Chief cells (stomach)

Action: Protein digestion

Regulation: Increased vagal stimulation, local acid

11

HCO3-

Source: Mucosal cells (stomach, duodenum, salivary glands, pancreas) and Brunner gland (duodenum)

Action: Neutralizes acid

Regulation: Increased by pancreatic and biliary secretion with secretin

Note: HCO3 is trapped in mucus that covers the gastric epithelium