What are the three phases to regulation of gastric secretions?
The physiologic stimulation of acid secretion has classically been divided into three interrelated phases: cephalic, gastric, and intestinal [6]. The cephalic phase is activated by the thought, taste, smell, and sight of food, and swallowing. It is mediated mostly by cholinergic/vagal mechanisms.
Which region produces the most HCl?
Parietal cells—Located primarily in the middle region of the gastric glands are parietal cells, which are among the most highly differentiated of the body’s epithelial cells. These relatively large cells produce both hydrochloric acid (HCl) and intrinsic factor.
Which of the following molecules can stimulate acid secretion from parietal cells of the stomach?
Gastrin secreted from G cells binds directly on parietal cells or stimulates acid secretion mediated by histamine release from ECL cells.
What controls gastric juice secretion?
Gastric acid secretion is under nervous and hormonal control. Gastrin, the major circulating stimulus of acid secretion, probably does not stimulate the parietal cells directly but acts to mobilize histamine from the ECL cells in the oxyntic mucosa. Histamine stimulates the parietal cells to secrete HCl.
How is gastric juice produced?
Gastric acid secretion is produced in several steps. Chloride and hydrogen ions are secreted separately from the cytoplasm of parietal cells and mixed in the canaliculi. Gastric acid is then secreted into the lumen of the gastric gland and gradually reaches the main stomach lumen.
How is gastric juice secreted?
1.2. Gastric HCl is secreted from the highly specialized parietal cells located in the corpus of the stomach, generating a H+ concentration in the gastric juice that is 3 million times greater than that in blood and tissue. The process is controlled by a complex system of endocrine cells and neurons.
What gland secretes gastrin?
stomach
Gastrin is a hormone produced by the stomach, which stimulates gastric motility and the release of gastric acid.
How is gastric acid secretion regulated?
Gastric acid secretion is regulated by three local hormones: acetylcholine, gastrin, and histamine. Of these three, acetylcholine has the largest effect. Parietal cells, G cells, and enterochromaffin-like cells are stimulated by acetylcholine released in response to vagus nerve simulation.
How is gastric acid produced?
Acid is secreted by parietal cells in the proximal two thirds (body) of the stomach. Gastric acid aids digestion by creating the optimal pH for pepsin and gastric lipase and by stimulating pancreatic bicarbonate secretion.