The black structures seen in the image are which cells?

• A. Astrocytes
• B. Neurons
• C. Microglia
• D. Oligodendrocytes

Answer: (A)

Recognizing astrocytes by their star-shaped morphology and the filamentous processes they extend throughout the CNS. When stained for GFAP or visualized with stains that highlight glial filaments, astrocytes appear as dark, branching networks due to their numerous processes radiating from a central body and often ensheathing blood vessels. This star-like arborization and distribution around neurons and capillaries matches what you’d expect for astrocytes, making them the best fit for the black structures in the image. Neurons would show large cell bodies with a prominent nucleus and nucleolus; microglia are smaller with condensed nuclei and limited processes; oligodendrocytes have smaller, rounder nuclei and are associated with myelin around axons, not a branched network.