Gastric acid secretion is the process by which the stomach produces hydrochloric acid (HCl) to aid in digestion. This acid helps break down food, activates digestive enzymes, and provides an acidic environment that kills harmful bacteria. The secretion is primarily stimulated by the presence of food, particularly proteins, and is regulated by hormones and nerve signals. The main cells responsible for gastric acid secretion are called parietal cells, located in the stomach lining. These cells release HCl in response to various stimuli, including the hormone gastrin, which is released when food enters the stomach. Proper gastric acid secretion is essential for effective digestion and nutrient absorption.