Mechanism of HCL Secretion

Mechanism of HCl Secretion: 

Mechanism of HCl Secretion Dr. Mahesh J. Patil P.G. Dept of Physiology

Introduction: 

Introduction Volume Parietal cells pH of acid is 0.8 Location of parietal cells

Theories: 

Theories Davenport and Fisher Theory Davies Theory Hollander Hypothesis

Davenport Theory: 

Davenport Theory HCl , hydrogen and chloride ions Secretion of H + CO 2 combines with water –Carbonic acid carbonic anhydrase H 2 CO 3 dissociates to release H + and HCO 3 - H + secreted into canaliculi in exchange for K + by primary active transport (H + - K + ATPase pump) HCO 3 by antiport in basolateral membrane of parietal cells into blood in exchange for Cl -

Secretion of Cl- : 

Secretion of Cl - High Intracellular negativity- Na + -K + pump Cl - channels on apical membrane of parietal cell These channels are activated by cAMP Na + -K + pump – 3Na + ions for 2K + pumped in K + ions diffuses out through K + channels located in basolateral membrane further increases intracellular negativity

PowerPoint Presentation: 

Omeprazole [Na + ] & [ Cl - ] similar to plasma [HCO 3 - ] & [K + ] much higher

Factors affecting: 

Factors affecting Stimulating Vagal stimulation Acetylcholine Gastrin Histamine Inhibiting Low pH<3 Intestinal influences Somatostatins Prostaglandins

Acetylcholine, Gastrin, and Histamine Directly and Indirectly Induce Acid Secretion by Parietal Cells : 

Acetylcholine, Gastrin , and Histamine Directly and Indirectly Induce Acid Secretion by Parietal Cells

Effect of eating on acid secretion : 

Effect of eating on acid secretion

Functions of HCl: 

Functions of HCl Breakdown of proteins Hinders growth of pathogenic bacteria Pepsinogen into active pepsin Stimulates flow of bile

Applied Aspects: 

Applied Aspects Achlorhydria Hyperacidity: Zollinger -Ellison syndrome Drugs Omeprazole H 2 receptor blocking drugs

THANK YOU: 

THANK YOU