Functions of hcla Turn pepsinogen into pepsin provide a medium of low pH favoring pepsin action; Kill many swallowed virulent organisms; Promote the secretion of pacreas &e bile Promote the absorption of calcium ferrum Pepsinogen Secreted by chief cells activate by hci FI unction: digest proteins into proteoses, peptones, polypeptides, with little free amino acids
Functions of HCl: Turn pepsinogen into pepsin & provide a medium of low pH favoring pepsin action; Kill many swallowed virulent organisms; Promote the secretion of pacreas & bile; Promote the absorption of calcium & ferrum Pepsinogen Secreted by chief cells & activate by HCl Function: digest proteins into proteoses, peptones, polypeptides, with little free amino acids
Mucus Secreted by neck surface mucous cells. cardiac pyloric glands Function form mucus-bicarbonate barrier Intrinsic factor Secreted by parietal cells Function: Promote the absorption of Vit B 12 k Regulation of gastric secretion Endogenous releasing substances Acetylcholine(Ach), gastrin histamine Somatostatin(SST)(release-inhibiting)
Mucus Secreted by neck & surface mucous cells, cardiac & pyloric glands Function: form mucus-bicarbonate barrier Intrinsic factor Secreted by parietal cells Function: Promote the absorption of Vit B12 * Regulation of gastric secretion Endogenous releasing substances Acetylcholine (ACh), gastrin & histamine Somatostatin (SST) (release-inhibiting)
H H pH2 粘液层 °NRF bblL Mucus-bicarbonate barrier
Mucus-bicarbonate barrier
C 胃泌素 Action of acetylcholine 胆碱能 组胺 细胞 gastrin 神经元 histamine on P the parietal ACh 泌素 cells
Action of acetylcholine, gastrin & histamine on the perietal cells
Gastric secretion in the digestive phase Cephalic phase Mechanisms Conditioned Unconditioned reflex Vagal efferent with Gastrin secretion through gastrin-releasing peptide GrP) Experiment: Sham feeding by pavlov Characteristics: Large quantity(30%o) High acidity digestive power
Gastric secretion in the digestive phase Cephalic phase Mechanisms: Conditioned & Unconditioned reflex Vagal efferent & with Gastrin secretion through gastrin-releasing peptide (GRP) Experiment: Sham feeding by Pavlov Characteristics: Large quantity (30%) High acidity & digestive power