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
What Kate Does week." VanDerWerff of the "LA Times", Ryan of the "Chicago Tribune", Sepinwall of "The Star-Ledger", Jensen of "Entertainment Weekly" and Mark Medley of the "National Post" also found the episode to contain humorous lines. This episode was watched by 11 million American viewers and 1.57 million Canadian viewers. What Kate Does "What Kate Does" is the 106th television episode of the American Broadcasting Company's "Lost" and third episode of the sixth season. It was written by executive producers Edward Kitsis and Adam Horowitz and directed in September 2009 by Paul Edwards. "What Kate Does" was first aired February 9, 2010,