Cerebrospinal fluid (CSF) is a clear fluid produced primarily in the choroid plexus, playing crucial roles in protecting the brain, providing buoyancy, and maintaining homeostasis. It is formed at a rate of 500ml/day and is essential for nutrient transport and diagnosing conditions like meningitis, with examination methods including lumbar puncture. The total intracranial volume is approximately 1700ml, with CSF accounting for 70-160ml.

1. CEREBROSPINAL FLUID
(CSF)

2. CONTENTS
• INTRODUCTION
• FORMATION
• COMPOSITION
• CIRCULATION
• FUNCTIONS
• APPLIED PHYSIOLOGY

3. INTRODUCTION
What is Cerebrospinal fluid?
Cerebrospinal fluid is a clear, colourless transparent tissue fluid that is
formed mainly in the ventricular plexus, distributed within the
ventricular system, basal cisterns and subarachnoid space.

4. FORMATION
About two thirds of CSF is secreted from the choroid plexus in the four
ventricles, mainly the two lateral ventricles.
One third of CSF is secreted by ependymal surfaces of all the ventricles
and by the arachnoid membranes.
In an adult, the intracranial volume is about 1700ml, of which the brain
measures 1200-1400ml and CSF acounts for 70-160ml.
CSF is formed at the rate of 500ml/day, However CSF is completely
replaced 3-4 times daily.

5. MECHANISM OF FORMATION
CSF is formed by a combination of passive diffusion, active transport
and facilitated diffusion

6. FORMATION

7. COMPOSITION

8. CIRCULATION

10. FUNCTIONS
• Protection– CSF acts as a hydraulic shock absorber preventing any
mechanical injury to the brain by coming in contact with the cranium.
• Buoyancy- The brain weighs approximately 1500g, CSF provides
buoyancy to support the weight of the brain.
• Homeostasis- Regulates the distribution of metabolites surrounding
the brain, provides a constant and controlled environment for the
brain cells.

11. FUNCTIONS
• Transport and clearance- Provides transport and exchange of
nutrients, waste products from the brain cells are excreted into the
CSF, which then drains into the bloodstream.
• Diagnosis of diseases- CSF can be used to diagnose diseases such as
meningitis.

12. APPLIED PHYSIOLOGY
• Lumbar Puncture- Sampling of CSF by lumbar puncture is an
important diagnostic tool in neurology.
• Hydrocephalus- Increase in the volume of CSF resulting in
enlargement of cerebral ventricles
• Examination of CSF (Meningitis)