What is its function?
Topic: Functions of cerebrospinal fluid
Answer
It acts as a SHOCK-ABSORBING CUSHION, protecting the delicate brain and spinal cord from mechanical injury, and it provides a MEDIUM FOR EXCHANGE of food materials, waste products and respiratory gases with the neurons.
Give BOTH functions — protection and exchange. They are different in kind, and an answer giving only the cushioning is incomplete.
THE PROTECTIVE ROLE is the more obvious: the brain effectively floats in this fluid, so a knock to the skull is absorbed rather than transmitted directly to the nervous tissue.
THE EXCHANGE ROLE is the one students forget. Nervous tissue has no direct blood supply reaching every neuron, so the CSF acts as the go-between, carrying nutrients and oxygen in and wastes away — rather as tissue fluid does elsewhere in the body.
It also keeps the pressure around the brain and cord constant.