Where is CSF found?
Brain and central canal of spinal cord
What are the functions of CSF?
- shock absorber
- chemical buffer
- buoyancy
- diffusion medium
What are the two structures responsible for CSF production?
- choroid plexi
- ependymal cell linings and vessels within the pia mater
Where are the choroid plexi found?
In each lateral ventricle with a pair in the 3rd and 4th ventricle
How is CSF produced through the choroid plexi?
Dialysis
How is CSF produced through ependymal cells?
Ultrafiltration of blood and active transport across the cells
What are ependymal cells connected by and what does it prevent?
- Tight junctions
- Molecules passing between cells
What do ependymal cells sit on and what dies this structure help to do?
- basement membrane
- provides support and protection against blood perfusion
What is the constitution of CSF?
- low protein (only albumin present)
- high concentrations of sodium and chloride
- very high concentrations of magnesium
- low potassium, calcium and glucose
How is CSF circulated?
Hydrostatic pressure
Describe the flow of the CSF from the lateral ventricles to the 4th ventricle
- Lateral ventricles
- Interventricular foramen
- 3rd ventricle
- Aqueduct of sylvius
- 4th ventricle
What are the two pathways for CSF after the 4th ventricle?
- flow down the central canal of the spinal cord
- circulate in the subarachnoid space
How does CSF escape the ventricular system?
Via the foramen of Lushka and Magendie
Where does the CSF in the brain flow if it escapes the ventricular system?
- subarachnoid space
- cerebromedullary cisterns
- cerebral hemispheres
Where does CSF in the spinal cord flow if it escapes the ventricular system?
- flows down the spinal cord in subarachnoid space
- lumbar cistern = dilation of the subarachnoid space as dura and arachnoid meninges carry on past the end of the spinal cord
How does CSF drain into the dorsal sagittal sinus?
Via arachnoid granulations (vili) - act as one ways valves helping to regulate CSF pressure
