In neurons, which cytoplasmic structure is abundant and stains basophilic due to its RNA content?

In neurons, which cytoplasmic structure is abundant and stains basophilic due to its RNA content?

• A. Mitochondria
• B. Golgi apparatus
• C. Nissl substance
• D. Peroxisomes

Answer: (C)

RNA-rich cytoplasmic granules in neuron cell bodies, known as Nissl substance, stain basophilic because they are essentially rough endoplasmic reticulum studded with ribosomes containing abundant ribosomal RNA. This material is plentiful in the soma and dendrites, reflecting the neuron’s need to synthesize proteins for maintenance and function. Basophilia arises from the RNA binding to basic dyes used in histology. Other organelles like mitochondria, Golgi apparatus, and peroxisomes exist in neurons but don’t form the same dense basophilic clusters seen with Nissl substance; mitochondria tend to stain more eosinophilic due to their protein-rich matrix, while the Golgi and peroxisomes are less conspicuous with routine stains.

RNA-rich cytoplasmic granules in neuron cell bodies, known as Nissl substance, stain basophilic because they are essentially rough endoplasmic reticulum studded with ribosomes containing abundant ribosomal RNA. This material is plentiful in the soma and dendrites, reflecting the neuron’s need to synthesize proteins for maintenance and function. Basophilia arises from the RNA binding to basic dyes used in histology. Other organelles like mitochondria, Golgi apparatus, and peroxisomes exist in neurons but don’t form the same dense basophilic clusters seen with Nissl substance; mitochondria tend to stain more eosinophilic due to their protein-rich matrix, while the Golgi and peroxisomes are less conspicuous with routine stains.