The tissue component stained red in the image is which of the following?

• A. Collagen
• B. Elastin
• C. Basement membrane
• D. Smooth muscle

Answer: (A)

When a stain like Van Gieson is used, the collagen fibers in the extracellular matrix take on a pinkish-red hue, while other components appear in contrasting colors (muscle/cytoplasm typically yellow). That distinct red staining identifies collagen as the tissue component highlighted in the image. Elastin fibers would appear dark with elastic stains, basement membranes are usually highlighted with PAS or silver stains, and smooth muscle tends to show a different color (often yellow) in this same staining scheme. So the red color directly points to collagen as the labeled component.