Biochemical Composition and Functions of Cerebrospinal Fluid

Cerebrospinal fluid (CSF) is a clear, colorless biological fluid that occupies the subarachnoid space and the ventricular system of the brain and spinal cord. It is one of the most functionally complex and biochemically rich biological fluids in the human body. As a dynamic fluid that interfaces directly with the central nervous system (CNS), CSF performs a multitude of indispensable physiological roles: it provides mechanical cushioning against trauma, maintains chemical homeostasis in the neural microenvironment, facilitates waste clearance via the glymphatic system, and serves as a conduit for the transport of neuroactive substances. The biochemical composition of CSF is exquisitely regulated and reflects the metabolic status of the brain and spinal cord. This report provides an in-depth examination of the biochemical constituents of CSF—including proteins, glucose, electrolytes, lipids, enzymes, neurotransmitters, and hormones—as well as an exhaustive discussion of its physiological functions and diagnostic significance.