Human cerebrospinal fluid (CSF) is a clear, colorless body fluid that surrounds and bathes the brain and spinal cord within the central nervous system (CNS). It occupies the ventricular system inside the brain, the subarachnoid space covering the brain and spinal cord, and the central canal of the spinal cord. CSF plays vital roles in mechanical protection, metabolic homeostasis, immune defense, and molecular transport in the nervous system.

Composition of Human Cerebrospinal Fluid

• Water content: Approximately 99% of CSF is water, making it a predominantly fluid medium bathing CNS tissues.
• Molecular constituents (about 1%): Include proteins, glucose, ions, vitamins, neurotransmitters, and other small molecules.
• Comparison to plasma: The composition of CSF is similar to blood plasma but differs notably in protein content (CSF is nearly protein-free compared to plasma) and electrolyte concentrations (notably lower chloride and higher sodium levels in CSF). Protein concentration in CSF ranges roughly from 15 to 40 mg/dL depending on the sampling site.
• Cell content: Normal CSF typically contains no red blood cells and fewer than 5 white blood cells/mm³. Elevated white cells indicate pleocytosis, suggestive of inflammation or infection.

Functions of Cerebrospinal Fluid

• Mechanical protection: CSF cushions the brain and spinal cord against mechanical shocks and impacts, providing a protective buoyancy that reduces effective brain weight within the skull.
• Metabolic support and waste removal: CSF participates in the transport of nutrients, ions, hormones, and metabolic waste products between blood and neural tissues, contributing to CNS homeostasis.
• Immunological roles: CSF contains immune cells and proteins essential for CNS immune surveillance and response.
• Molecular transport: It facilitates distribution of neuromodulators and neurotransmitters across the CNS environment.
• Maintaining intracranial pressure: CSF dynamics play a key role in controlling intracranial pressure and volume balance.

Clinical and Research Importance

• Diagnostic sampling: CSF is frequently sampled via lumbar puncture to diagnose neurological diseases such as infections (meningitis), inflammatory disorders (multiple sclerosis), and hemorrhage.
• Biomarker discovery: CSF analysis reveals protein and molecular changes associated with neurodegenerative diseases (e.g., Alzheimer’s, Parkinson’s), brain tumors, and CNS injury.
• Blood-CSF and blood-brain barriers: CSF composition is regulated by the blood-CSF barrier at the choroid plexus and the blood-brain barrier at the brain parenchyma, influencing permeability and molecular exchange.
• Therapeutic delivery: CSF provides a route for drug delivery into the CNS.
• Research tool: Study of CSF components aids in understanding neural physiology, pathology, and brain metabolism.

Human cerebrospinal fluid is an essential fluid medium supporting the central nervous system’s mechanical protection, metabolic balance, and immunological integrity. Its distinct composition and dynamic circulation reflect its specialized role in neural health and disease. CSF analysis remains a cornerstone in neurological diagnostics and research, advancing our understanding of CNS physiology and pathophysiology.

⚠ “Please note that the products listed below are available on request only. For any inquiry, please contact our technical support team and refer to the desired catalog number when sending your request.”