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The parietal cell membrane is dynamic; the numbers of canaliculi rise and fall according to secretory need. This is accomplished by the fusion of canalicular precursors, or tubulovesicles, with the membrane to increase surface area, and the reciprocal endocytosis of the canaliculi (reforming the tubulovesicles) to decrease it. [2]
The hormone gastrin and the vagus nerve trigger the release of both pepsinogen and HCl from the stomach lining when food is ingested. Hydrochloric acid creates an acidic environment, which allows pepsinogen to unfold and cleave itself in an autocatalytic fashion, thereby generating pepsin (the active form). Pepsin cleaves the 44 amino acids ...
The gastric chief cell (also known as a zymogenic cell or peptic cell) is a cell in the stomach that releases pepsinogen [1] and chymosin.Pepsinogen is activated into the digestive enzyme pepsin when it comes in contact with hydrochloric acid produced by gastric parietal cells. [2]
The gastric hydrogen potassium ATPase or H + /K + ATPase is the proton pump of the stomach.It exchanges potassium from the intestinal lumen with cytoplasmic hydronium [2] and is the enzyme primarily responsible for the acidification of the stomach contents and the activation of the digestive enzyme pepsin [3] (see gastric acid).
The parietal cell releases bicarbonate into the bloodstream in the process, which causes a temporary rise of pH in the blood, known as an alkaline tide. The gastric juice also contains digestive enzymes produced by other cells in the gastric glands – gastric chief cells. Gastric chief cells secrete an inactivated pepsinogen.
In biology, membrane fluidity refers to the viscosity of the lipid bilayer of a cell membrane or a synthetic lipid membrane. Lipid packing can influence the fluidity of the membrane. Viscosity of the membrane can affect the rotation and diffusion of proteins and other bio-molecules within the membrane, there-by affecting the functions of these ...
Chemiosmosis is the movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient.An important example is the formation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H +) across a membrane during cellular respiration or photosynthesis.
The microelectrode method for measuring pH i consists of placing a very small electrode into the cell’s cytosol by making a very small hole in the plasma membrane of the cell. [19] Since the microelectrode has fluid with a high H+ concentration inside, relative to the outside of the electrode, there is a potential created due to the pH ...