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They contain an extensive secretory network of canaliculi from which the HCl is secreted by active transport into the stomach. The enzyme hydrogen potassium ATPase (H + /K + ATPase) is unique to the parietal cells and transports the H + against a concentration gradient of about 3 million to 1, [ citation needed ] which is the steepest ...
H + is pumped into the stomach by exchanging it with K +. This process also requires ATP as a source of energy; however, Cl − then follows the positive charge in the H + through an open apical channel protein. HCO 3 − secretion occurs to neutralize the acid secretions that make their way into the duodenum of the small intestine.
The churning motion of the stomach was described among other findings. [53] In the 19th century, it was accepted that chemical processes were involved in the process of digestion. Physiological research into secretion and the gastrointestinal tract was pursued with experiments undertaken by Claude Bernard, Rudolph Heidenhain and Ivan Pavlov.
The secretions of the different exocrine gastric gland cells produce a watery, acidic fluid into the stomach lumen called gastric juice. [5] [6] Gastric juice contains water, hydrochloric acid, intrinsic factor, pepsinogen, and salts. Adults produce around two to three litres of gastric juice per day. [5]
Secretion of gastrin is stimulated by food arriving in stomach. The secretion is inhibited by low pH. Secretin – is in the duodenum and signals the secretion of sodium bicarbonate in the pancreas and it stimulates the bile secretion in the liver. This hormone responds to the acidity of the chyme.
The lowest pH of the secreted acid is 0.8, [5] but the acid is diluted in the stomach lumen to a pH of between 1 and 3. There is a small continuous basal secretion of gastric acid between meals of usually less than 10 mEq/hour. [6] There are three phases in the secretion of gastric acid which increase the secretion rate in order to digest a ...
In contrast, expectorants lubricate your airway, which helps loosen up the mucus and make the secretions in your airway thinner. By loosening up the mucus, expectorants make your cough more ...
The bicarbonate buffer system plays a vital role in other tissues as well. In the human stomach and duodenum, the bicarbonate buffer system serves to both neutralize gastric acid and stabilize the intracellular pH of epithelial cells via the secretion of bicarbonate ion into the gastric mucosa. [1]