Which retinal glial cell spans the thickness of the retina and provides structural support?

• A. Astrocytes
• B. Müller glial cells
• C. Microglia
• D. Rods

Answer: (B)

Müller glial cells run the entire thickness of the retina, extending from the inner limiting membrane at the vitreous surface to the outer limiting membrane near the photoreceptors. This radial arrangement creates a continuous scaffold that supports the layered retinal structure, helping to maintain its shape and organize the neurons. Their processes span all retinal layers, anchoring cells in place and contributing to homeostasis by regulating the extracellular environment and metabolism. This spanning glial cell is the main structural support for the retina. By contrast, astrocytes are CNS glia located mainly around the nerve fiber layer and vessels, microglia are immune cells, and rods are photoreceptor neurons, not glial cells.