GI 1 Flashcards
Describe the effect of Acetylcholine on the GI system
Acetylcholine is excitatory neurotransmitter that causes:
Vasodilation
Increased secretions
Smooth muscle contraction.
Describe the effect of Serotonin on the GI system
Excitatory
Vasodilation
Smooth muscle contraction
Secretion stimulus
Describe the effect of Norepinephrine on the GI system
Inhibitory
- Vasoconstriction
- Inhibits smooth muscle contraction
- Decreases secretions.
Describe the effect of Dopamine on the GI system
Inhibitory
Acts by inhibiting the ENS!
Describe the effect of Nitric Oxide on the GI system
Causes smooth muscle relaxation
Describe the effect of Vasoactive intestinal peptide on the GI system
Inhibitory causing smooth muscle relaxation.
What effect does VIP have on the blood supply to the GI?
Causes vasodilation.
What are the key regulators of the GI smooth muscle membrane potential?
Ach stimulates contractions
VIP and NO inhibit contractions.
What effect does CCK have and where is it released?
Released by the duodenum in response to Fat content!
Leads to increased enzyme secretion
Decreased emptying
What effect does Gastrin have and where is it released?
Released from G-cells and promotes gastric acid `secretion.
What effect does Motilin have on the stomach and where is it released?
Released from upper GI causes smooth muscle contraction in the stomach and duodenum.
What effect does somatostatin have and where is it released from?
somatostatin is released from D cells. Decreases acid secretion Increases fluid absorption Decreases smooth muscle contraction Decreases secretions and bile flow!
What effect do Prostaglandins have?
These decrease acid secretion and increase blood flow as well as mucus and bicarb secretion.
What effect does histamine have and what cells release it
Released from the ECL cells causes increased acid production.
