PSIO 532 Study Guide - Final Guide: Vocal Folds, Hyoid Bone, Trachea
Graduate Physiology – GI Tract
Phases of GI Regulation
Even when you just see meal or smell a
good meal or talk about, you start
having GI responses start to secreting
some acid or enzyme
The intensity of the regulation is
different than actually eating the meal
itself; just talking about it wont release
that much CCK release; otherwise it
wouldn’t be much of a good regulation
Cephalic Phase: this is the initial phase
where you start to prepare for the digestion
Gastric Phase: you have food distending your stomach that trigger a lot of the
receptors (mechanoreceptors [volume & pressure], neuronal endings) start
sending signals for contraction to cause secretion
Intestinal Phase: chemical receptors (chemoreceptors – amino acids, fatty acids,
pH) that sense the food components; the food components are being sensed by
cells that make the CCK, secretin and GLP
Osmoreceptors senses the osmolarity (cell concentration)
Mouth, Pharynx and Esophagus
Chewing and Cephalic Phase
oSight, smell, taste & chewing leads to increase the secretion of HCl (the pathway
is parasympathetic nerves to the enteric nervous system)
oGastric secretion occurs even before the food enters the stomach, especially
when its being eaten greater the appetite, the greater the stimulation
Salivary Secretions
Some secretion occurs in the mouth (beginning of the GI
tract)
Minor digestion occurs in the mouth due to the saliva; the
more you chew your food, the sweeter it becomes due to the more secretion of
saliva (amylase in the saliva can digest carbohydrates into sugars)
Saliva also have mucus lubricant that has some immune functions
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Document Summary
Even when you just see meal or smell a good meal or talk about, you start having gi responses start to secreting some acid or enzyme. The intensity of the regulation is different than actually eating the meal itself; just talking about it wont release that much cck release; otherwise it wouldn"t be much of a good regulation. Cephalic phase: this is the initial phase where you start to prepare for the digestion. Gastric phase: you have food distending your stomach that trigger a lot of the receptors (mechanoreceptors [volume & pressure], neuronal endings) start sending signals for contraction to cause secretion. Intestinal phase: chemical receptors (chemoreceptors amino acids, fatty acids, ph) that sense the food components; the food components are being sensed by cells that make the cck, secretin and glp. Osmoreceptors senses the osmolarity (cell concentration) Some secretion occurs in the mouth (beginning of the gi tract)
