Stomach -- site where food is converted to a thick fluid for most efficient enzymatic digestion of macromolecules.

Examine a section of the fundic region of the stomach (slide 101).

• Identify first the layers and sublayers (Fig. 15-15), noting that the simple columnar epithelium invaginates into gastric pits, which are tightly packed together side-by-side
• These lead into the gastric glands which extend down all the way to the thin muscularis mucosa. Cells of the lamina propria are seen scattered loosely around the gastric pits.

Why is the lamina propria of the stomach more difficult than usual to study histologically?

On the same slide (101), find a region of mucosa in which the gastric glands are cut longitudinally. Starting at the surface, identify the mucus-secreting cells (called surface and neck cells depending on their proximity to the surface lining the stomach cavity), the large eosinophilic parietal cells, and the smaller, more basophilic peptic cells (Figs. 15-18 through 15-24). (Image courtesy of GERD Information Resource Center)

How would you classify the gastric glands morphologically?

Why are the products of all three of these cells critical for proper digestion of food in the stomach?

Using electron micrographs in the atlas, study the ultrastructural features of peptic cells (Fig. 15-24) and parietal cells (Fig. 15-22).

What highly unusual structures of parietal cells make them uniquely suited for their function?

On to the pyloric glands and small intestine.