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1. The taste or smell of food, tactile
sensations of food in the mouth, or
even thoughts of food stimulate the
medulla oblongata (green arrow).
2. Parasympathetic action potentials
the stomach (pink arrow).
plexus of the stomach.
4. Postganglionic neurons stimulate
and stimulate gastrin secretion by
endocrine cells.
circulation back to the stomach
(purple arrow), where it stimulates
secretion by parietal and chief cells.
Cephalic Phase
Tactile sensation in mouth
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The taste or smell of food, tactile sensations of food in the mouth, or even thoughts of food stimulate the medulla oblongata (green arrow).
Cephalic Phase
Tactile sensation in mouth
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Parasympathetic action potentials are carried by the vagus nerves to the stomach (pink arrow).
Cephalic Phase
Vagus nerves
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Preganglionic parasympathetic vagus nerve fibers stimulate postganglionic neurons in the enteric plexus of the stomach.
Cephalic Phase
Vagus nerves
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Cephalic Phase
Postganglionic neurons stimulate secretion by parietal and chief cells and stimulate gastrin secretion by endocrine cells.
Gastrin
Stomach
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Cephalic Phase
Gastrin is carried through the circulation back to the stomach (purple arrow), where it stimulates secretion by parietal and chief cells.
Gastrin
Circulation
Secretions
stimulated
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Local reflexes
stimulated by
stomach distention
parasympathetic reflex. Action potentials
medulla oblongata (green arrow).
secretions (pink arrow).
local reflexes that increase stomach
secretions (purple arrow).
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Local reflexes
stimulated by
stomach distention
Distention of the stomach activates a parasympathetic reflex. Action potentials are carried by the vagus nerves to the medulla oblongata (green arrow).
Gastric Phase
Vagus nerves
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Gastric Phase
Decreased
gastric
secretions
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Gastric Phase
Local reflexes
stimulated by
stomach distention
Distention of the stomach also activates local reflexes that increase stomach secretions (purple arrow).
Distention
Stomach
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1. Chyme in the duodenum with
a pH less than 2 or containing
fat digestion products (lipids)
inhibits gastric secretions by
to the medulla oblongata
(green arrow) inhibit motor
action potentials from the
medulla oblongata (pink arrow).
secretion (orange arrows).
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Chyme in the duodenum with a pH less than 2 or containing fat digestion products (lipids) inhibits gastric secretions by three mechanisms.
pH<2
or lipids
Intestinal Phase
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Intestinal Phase
Sensory vagal action potentials to the medulla oblongata (green arrow) inhibit motor action potentials from the medulla oblongata (pink arrow).
pH<2
or lipids
Mechanism One
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Intestinal Phase
pH<2
or lipids
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Secretin, gastric inhibitory polypeptide, and cholecystokinin produced by the duodenum (brown arrows) inhibit gastric secretions in the stomach.
pH<2
or lipids