Gastric acid network (called canaliculi) from which the hydrochloric acid is secreted into the lumen of the stomach. The pH of gastric acid is 1.5 to 3.5 in the human stomach lumen, the acidity being maintained by the proton pump H/K ATPase. 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 highly acidic environment in the stomach lumen causes proteins from food to lose their characteristic folded structure (or denature). This exposes the protein's peptide bonds. The gastric chief cells of the stomach secrete
Stomach oil Stomach oil Stomach oil is the light oil composed of neutral dietary lipids found in the proventriculus (fore-gut) of birds in the order Procellariiformes. All albatrosses, procellarids (gadfly petrels and shearwaters) and northern and austral storm petrels use the oil. The only Procellariiformes that do not are the diving petrels. The chemical make up of stomach oil varies from species to species and between individuals, but almost always contains both wax esters and triglycerides. Other compounds found in stomach oil include glycerol ethers, pristane and squalene. Stomach oil has low viscosity and will solidify into a hard wax if allowed