Introduction The CSF contributes to homeostasis in three main ways Composition of CSF FORMATION OF CEREBROSPINAL FLUID Cerebrospinal Fluid Pressure Cerebrospinal fluid circulation ABSORPTION OF CEREBROSPINAL FLUID The Functions of the Cerebrospinal Fluid Clinical applications References

1. CEREBROSPINAL
FLUID
PANDIAN M
D.Y. PATIL MEDICAL COLLEGE, KOP

2. SLO
• INTRODUCTION
• The CSF contributes to homeostasis in three main ways
• COMPOSITION OF CSF
• FORMATION OF CEREBROSPINAL FLUID
• CEREBROSPINAL FLUID PRESSURE
• CEREBROSPINAL FLUID CIRCULATION
• ABSORPTION OF CEREBROSPINAL FLUID
• THE FUNCTIONS OF THE CEREBROSPINAL FLUID
• CLINICALAPPLICATIONS
• REFERENCES

3. INTRODUCTION
•The CSF is found in the
•ventricles, Subarachnoid space & Spinal
cord.
•It has a volume of about 150 ml.
•It is a clear, colorless fluid and possesses,
•In solution, inorganic salts similar to those in the
blood plasma.

4. •The glucose content is about half that of
blood, and there is only a trace of protein.
•Only a few cells are present, and these are
lymphocytes.
•The normal lymphocyte count is 0 to 3 cells
per cubic millimeter.

5. The CSF contributes to homeostasis in three main ways:
1. Mechanical protection.
• CSF serves as a shock-absorbing Medium that protects the
delicate tissues of the brain and
• spinal Cord from jolts that cause them to hit the bony walls
of the cranial cavity and vertebral canal.
• The fluid also Buoys the brain so that it “floats” in the
cranial cavity.

6. 2. Chemical protection.
•CSF provides an optimal chemical Environment
for accurate neuronal signaling.
•Even slight Changes in the ionic composition of
CSF within the brain can Seriously disrupt
production of action potentials and Postsynaptic
Potentials.

7. 3. Circulation.
CSF allows exchange of nutrients and waste Products
between the blood and nervous tissue.

8. Composition of CSF

13. CHOROID PLEXUS IN A LATERAL VENTRICLE.

14. FORMATION OF CEREBROSPINAL FLUID
SITE OF FORMATION
•CSF is formed by choroid plexuses, situated within the
ventricles.
•Choroid plexuses are tuft of capillary projections present
inside the ventricles.
•It’s covered by pia mater and ependymal covering.
•A large amount of CSF is formed in the lateral ventricles.

15. MECHANISM OF FORMATION
•CSF is formed by the process of secretion that
involves active transport mechanism.
•Formation of CSF does not involve ultrafiltration or
dialysis.

17. CEREBROSPINAL FLUID PRESSURE
•The normal pressure in the CSF When one is lying in a
horizontal position averages 130 Millimeters of water
(10 mm Hg),
•although this may be as low as 65 millimeters of water
or as high as 195 millimeters of water even in the
normal healthy person.
•The pressure of the CSF is kept remarkably constant.

18. •In the lateral recumbent position, the pressure, as
measured by spinal tap, is about 60 to 150 mm of
water.
•This pressure may be raised by straining, coughing,
or compressing the internal jugular veins in the
neck

19. CEREBROSPINAL FLUID CIRCULATION

22. ABSORPTION OF CEREBROSPINAL FLUID
•CSF is mostly absorbed by the arachnoid villi into
dural Sinuses and spinal veins.
•Small amount is absorbed along the perineural
spaces into cervical lymphatics and perivascular
spaces.
•The mechanism of absorption is by filtration due to
Pressure gradient between hydrostatic pressure in
the Subarachnoid space fluid

23. •The pressure that exists in the dural sinus blood.
•Colloidal substances pass slowly and
crystalloids are absorbed rapidly.
•Normally, about 500 ml of CSF is formed
everyday and an equal amount is absorbed.

26. THE FUNCTIONS OF THE CEREBROSPINAL
FLUID
1. Cushions and protects the central nervous system from
trauma
2. Provides mechanical buoyancy and support for the brain
3. Serves as a reservoir and assists in the regulation of the
contents of the skull
4. Nourishes the central nervous system
5. Removes metabolites from the central nervous system
6. Serves as a pathway for pineal secretions to reach the
pituitary gland

27. CLINICAL APPLICATIONS
HYDROCEPHALUS
•Hydrocephalus refers to an abnormal accumulation of
CSF in the cranium.
Causes of hydrocephalus include:
• Obstruction to CSF circulation,
• Excessive production of CSF and
• Interference with absorption of CSF.

28. TYPES OF HYDROCEPHALUS
1. Internal or non-communicating hydrocephalus
occurs when obstruction is within the ventricular
system
2. External or communicating hydrocephalus occurs
when obstruction is in subarachnoid space or arachnoid
villi.

29. Lumbar and cisternal puncture
•Lumbar puncture refers to the tapping of CSF from
the lumbar cistern.
•It is performed by inserting a Needle in between the
L2 and L3 or L3 and L4 vertebrae into the
subarachnoid space within vertebral canal,
•as there is No risk of damage to spinal cord as it ends
at the level of first Lumbar vertebra.

30. Cisternal puncture refers to the tapping of CSF from
the Cisterna magna.
•To do this, a needle is passed through the Posterior
atlanto-occipital membrane forwards and upwards
•To a depth of 4.5 cm from the surface.

31. USES OF LUMBAR PUNCTURE
Lumbar puncture is used for:
1. Collecting CSF for diagnostic purposes
2. Injecting drugs (intrathecal injection) for spinal
Anesthesia, analgesia and chemotherapy
3. Measuring the pressure exerted by CSF.

32. REFERENCES
• TEXT BOOK OF MEDICAL PHYSIOLOGY
• GUYTON & HALL
• HUMAN PHYSIOLOGY
• VANDER
• TEXT BOOK OF MEDICAL PHYSIOLOGY
• INDUKURANA
• PRINCIPLES OF ANATOMY AND PHYSIOLOGY
• TOTORA
• NET SOURCE

33. THANK YOU . . .