Final answer:
The gastric epithelium contains several secretory cells: parietal cells (secrete hydrochloric acid and intrinsic factor), chief cells (secrete pepsinogen), mucous neck cells (secrete acidic mucus), and enteroendocrine cells (release hormones like gastrin). These cells contribute to the digestive process within the stomach.
Step-by-step explanation:
Within the gastric epithelium of the stomach, there are several types of secretory cells that contribute to digestion. The gastric glands are primarily composed of these cells, each with a specific function:
- Parietal cells – Produce hydrochloric acid (HCI), which creates a highly acidic environment in the stomach (pH 1.5 to 3.5), activating pepsin and aiding in protein digestion. They also secrete intrinsic factor, which is crucial for vitamin B12 absorption in the small intestine.
- Chief cells – These cells are responsible for secreting pepsinogen, the inactive precursor to pepsin, which is a protein-digesting enzyme activated by the acidic environment.
- Mucous neck cells – Secrete a thin, acidic mucus, different from the mucus produced by surface epithelium cells, with a currently unknown role.
- Enteroendocrine cells – These cells release various hormones, such as gastrin from G cells, into the lamina propria's interstitial fluid.
The glands of the fundus and body of the stomach are where most chemical digestion occurs, with a larger variety of secretory cells compared to other regions like the cardia and pylorus, which primarily contain mucus-secreting cells.