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GASTROINTESTINAL PHYSIOLOGY

Major Cl Hormones

LEGEND

Thick linę indicatcs prinwry action

Thin linę indicates secondary anion

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OjpN

Hormon.	Neuroendoc rim* Celi Typc and Location	Stimulus for Secretion	Primary Action	Other Actions
Gosom	Gcell Stornach, duodenum	Vaj$us, distention.	Stimulate HCI secretion	Inhibit gastric emptying
Sca«nr	Duódcnom	Acid		Inhibit gastric secretion, inhibit gasfrit ofoiiiily, and stimulate bile duet seuclion 0l>f»O and MCO
Cholecystokinin	1 ccii Duodenum, lejunum	Fal vagus	acirwr ęells and contract the gallbladder	Inhibit gastric motility
GlP*	K celi Duodenum, |ejunum	Fat	Inhibit gastric secretion and motjlity	Stimulate insulin secretion
Modlin	M celi Duodenum, jejunum		Incrcased motifity and initiates the MMC

Figurę 7.8 Major Gl Hormones

The funcłion of Ihe Gl tract i$ controlled by both neural (primarily parasympathetic fibers of Ihe vagus nerve) and hormonal mecha-nisms. Fiv<? major Gl hormones have boen identificd. In addition, a large number of other “candidatc hormones/' produced by neu-roendocrine cdls scattered Ihrough the mucosa ot the stornach and inleslines, also play a role in regulating and coordinating Gl lra< l

funcłion (not listed). The primary, and some ot the other secondary, actions of Ihe five Gl hormones are summarized. The "migrating motor (or myoelectricł complcx" (MMC) occurs between meals wrth a period of 1 to 2 hours. It consists of a wave of peristalsis that serye¹-to dean Ihe Gl Iract by moving residua! food particles drstally.

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