Gastric acid secretion and the stomach

This session centers on gastric acid secretion and the stomach, offering a structured look at the anatomy and specialized cell types of the stomach and how they contribute to its digestive functions. We will examine the mechanisms of hydrochloric acid secretion, its crucial roles in protein digestion and microbial defense, and the tightly regulated control of acid production. The lecture will also address the stomach's protective barriers against self digestion and common disorders resulting from imbalances in acid secretion or mucosal defense. Understanding these concepts is vital for appreciating both healthy digestion and related diseases. Let's explore the structure of the stomach, a key digestive organ located between the esophagus and small intestine. Its wall has several layers with the innermost mucosa lined by simple columnar epithelium forming gastric pits. Beneath long tubular gastric glands open into these pits, containing mucous neck cells for protective mucus, chief cells producing pepsinogen, parietal cells secreting hydrochloric acid and intrinsic factor, and enteroendocrine cells releasing hormones like gastrin. This organization supports digestion and protects the mucosa. At the heart of the stomach's digestive role is the secretion of hydrochloric acid or HCL by parietal cells. HCL lowers the pH dramatically, creating an acidic environment ideal for activating pepsinogen into pepsin, which initiates protein digestion. The acidity also denatures