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Gastric Secretion: I

GASTROINTESTINAL PHYSIOLOGY

Neurocrine Regulalion of Acid Sccrction

Cephalic

(central)

stimulation

Vagal

eitcront

Sight

Smell and taste    Hypoglycemia

Vagovagal llong loop) reflcx

_x_

Vagal

afferenl

JOWAC

©WSI

RA^_«o

Gastric acid secretion initiated and modulated by nervous system via central stimulation through vagal efferents and enteric plexus and by intramural (short) feedback loop and a second (long, or vagovagali feedback loop, both stimulated by gastric antral distcntion

Figurę 7.13 Vac.al Control of Gastric Secretion

>tric secretion, in response to sight, smell, lasie, and chewing or • d. is initiated and modulated by the vagus nerves of the auto-■ nic nervous system. This initial stimulation of secretomotor activ-is referred to as ilu; “ccphalic phase." The vagal stimulation acts via the enteric ner\-ous system to initiate gastric secretion ot a< icf (HCI) and gastrin. The presence of acid, amino acids. and peptides. as well as gastric distention, effectively stimulates the next phase of gastnc secretion. termed the "gastric phase."

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