What is the primary function of astrocytes in the CNS?

• A. Exchange Nutrients
• B. Dispose of Debris
• C. Myelinate Axons
• D. Produce Cerebrospinal Fluid

Answer: (A)

Astrocytes are the metabolic support system for neurons. They closely interact with blood vessels, taking up glucose and other nutrients from the bloodstream and helping deliver energy substrates to neurons—for example, converting glucose to lactate that neurons can use. They also help keep the neuronal environment stable by buffering ions and clearing neurotransmitters, all of which keeps neurons functioning efficiently. This role of facilitating nutrient exchange and metabolic support is why nutrient exchange is the best description of their primary function. In comparison, debris disposal is handled mainly by microglia, myelination by oligodendrocytes, and cerebrospinal fluid production by ependymal cells.