Which tissue serves as a control tissue for fat demonstration?

• A. Adrenal
• B. Liver
• C. Brain
• D. Kidney

Answer: (A)

The presence of abundant intracellular lipids in a specific tissue makes it an ideal reference for demonstrating fat. In the adrenal cortex, lipid droplets are numerous and well-distributed within the steroidogenic cells. These lipids tend to appear as clear vacuoles even after routine paraffin processing, so this tissue reliably shows fat-related features and serves as a consistent positive reference when practicing fat demonstration techniques or staining.

Other tissues don’t provide the same reliability. The liver’s fat content can vary with metabolic state, so it’s less consistent as a standard control. Brain tissue has relatively little cytoplasmic lipid, limiting its usefulness for this purpose. The kidney contains little intracellular fat in most of its parenchyma, making it a poor reference for demonstrating fat.