Gliogenesis begins relative to neurogenesis, and which glial cell types are produced?

Gliogenesis begins relative to neurogenesis, and which glial cell types are produced?

• A. Begins before neurogenesis; neurons and astrocytes
• B. Begins after major neurogenesis; astrocytes and oligodendrocytes
• C. Begins simultaneously with neurogenesis; microglia and ependymal cells
• D. Begins after neurogenesis; neurons and oligodendrocytes

Answer: (B)

Gliogenesis follows neurogenesis: after neurons are largely formed, neural progenitors switch to making glial cells to support and insulate the developing neural network. The main glial products are astrocytes and oligodendrocytes. Astrocytes provide metabolic support, regulate ion balance, and contribute to the blood–brain barrier, while oligodendrocytes create myelin sheaths around axons to speed signaling. Microglia come from hematopoietic precursors and migrate into the CNS, not from the neural progenitors driving gliogenesis, and ependymal cells arise from the neuroepithelium lining the ventricles in a different lineage. Hence, gliogenesis begins after major neurogenesis and yields astrocytes and oligodendrocytes.

Gliogenesis follows neurogenesis: after neurons are largely formed, neural progenitors switch to making glial cells to support and insulate the developing neural network. The main glial products are astrocytes and oligodendrocytes. Astrocytes provide metabolic support, regulate ion balance, and contribute to the blood–brain barrier, while oligodendrocytes create myelin sheaths around axons to speed signaling. Microglia come from hematopoietic precursors and migrate into the CNS, not from the neural progenitors driving gliogenesis, and ependymal cells arise from the neuroepithelium lining the ventricles in a different lineage. Hence, gliogenesis begins after major neurogenesis and yields astrocytes and oligodendrocytes.