The Hematoxylin & Eosin control slide uses tissue from which location?

• A. Small Intestine
• B. Kidney
• C. Liver
• D. Fat

Answer: (A)

The key idea here is using a control tissue that shows a variety of structures so you can verify that both hematoxylin and eosin staining are working across different cell types and tissue components. The small intestine is used because it presents multiple elements in one slide: the simple columnar epithelium with nuclei in absorptive cells, goblet cells that add mucin, the underlying lamina propria, and the layers of muscularis mucosae and muscularis externa. This mix lets you see nuclei stain blue/purple with hematoxylin, cytoplasm and connective tissue stain pink with eosin, and it also lets you observe how well mucus in goblet cells is preserved. If the stain and processing are performing properly, you’ll get clear, contrasting detail across these features.

Other tissues might not provide that same breadth on a single slide. For example, fat can lose its lipid during processing and appear as empty spaces, which isn’t ideal for evaluating staining quality; liver or kidney show specific but limited features compared to the diverse architecture of the small intestine.