Which of the following is a function of CSF?

• A. Buoyancy, nutrient delivery, and waste clearance.
• B. Production of neurotransmitters.
• C. Storage of ions.
• D. Inhibition of neural activity.

Answer: (A)

Cerebrospinal fluid primarily creates a stable, supportive environment for the brain by providing buoyancy, delivering nutrients, and clearing wastes. Buoyancy lets the brain float, reducing the effective weight on its base and protecting neural tissue from mechanical stress. CSF circulates through the ventricles and subarachnoid space, exchanging with interstitial fluid to supply nutrients like glucose and amino acids while carrying away metabolic byproducts. This waste clearance helps keep the neural environment clean and balanced, supporting healthy neural function.

Production of neurotransmitters happens in neurons and glial cells, not in the CSF. While CSF does carry ions and small signaling molecules, it isn’t a storage site for ions; ionic balance is maintained by transport processes across the blood-brain barrier and the choroid plexus. Inhibition of neural activity is achieved by neural circuits and neurotransmitters, not directly by CSF.