10 Questions
What is the consequence of CSF leakage due to traumatic fracture base of the skull or congenital conditions?
Reduced amount of CSF
What is the characteristic of CSF in subarachnoid hemorrhage?
Presence of RBCs in the CSF
What is the complication of reduced CSF pressure in the region proximal to the site of the obstruction?
Herniation of the medulla oblongata in the foramen magna
What is the role of CSF in investigating CNS pathologies?
It is a sensitive tool to investigate conditions related to CNS pathologies
What is the characteristic of CSF in meningitis?
High CSF cell count and high protein content
What is the consequence of iatrogenic CSF leakage?
Reduced amount of CSF
What is the sign of meningitis in children?
Bulging anterior fontanelle
What is the consequence of CSF obstruction?
Increased CSF pressure in the region proximal to the site of the obstruction
What is the role of CSF in CNS infections?
It is a sensitive tool to investigate conditions related to CNS pathologies
What is the complication of herniation of the medulla oblongata in the foramen magna?
Sudden death
Study Notes
Ventricular System and CSF Formation
- Ependymal cells in the choroid plexus are responsible for CSF formation through extraction from the blood and release into ventricular cavities, not through synthesis and secretion.
- Tanycytes, a type of ependymal cell, possess foot processes that pierce the basement membrane of the plexus and astrocytes to encircle the blood capillary.
- 70% of CSF is formed through this process, while the remaining 30% is from metabolic and capillary bed exudation.
CSF Composition and Characteristics
- CSF composition is comparable to blood, but with different proportions.
- Glucose concentration in CSF is 3/4th of blood glucose levels.
- Protein concentration in CSF is 2500g/dl, compared to 6500g/dl in plasma.
- Na+, Cl-, and Mg2+ concentrations in CSF exceed those in blood, while K+ and Ca2+ concentrations are lower.
- CSF pressure is 10-15 mmHg.
- CSF contains mainly lymphocytes, with around 5 cells/cc.
CSF Circulation and Drainage
- Total CSF volume is approximately 140ml, with 25ml in the intraventricular space and 115ml in the subarachnoid space.
- CSF turnover rate is 50% every 6 hours.
- CSF drains from ventricular cavities to the subarachnoid space through foramina of Luschka and Magendie in the fourth ventricle.
- From the subarachnoid space, CSF drains to the superior sagittal sinus through arachnoid granulations.
CSF Functions
- CSF carries the weight of the brain, reducing its weight from 1500g to 50g.
- CSF acts as a shock absorber, protecting the brain from injury during head movement.
- CSF maintains homeostatic stability of the brain and serves as an indicator for brain abnormalities.
Abnormalities of Ventricles and CSF
- Dilated lateral ventricle is associated with conditions like congenital hydrocephalus, schizophrenia, Alzheimer's disease, and dementia.
- Hydrocephalus results from imbalance between CSF production and drainage or obstruction in the CSF pathway.
- Reduced CSF amount can occur due to leakage, congenital conditions, or iatrogenic complications.
CSF as a Diagnostic Tool
- CSF analysis is used to investigate CNS pathologies, such as infections, which are associated with high CSF cell count and protein contents.
- Presence of RBCs in CSF is diagnostic for subarachnoid hemorrhage.
- High CSF pressure is a common sign of meningitis.
Learn about the process of cerebrospinal fluid formation and circulation in the ventricular system of the brain. Discover the role of ependymal cells, tanycytes, and astrocytes in this process. Test your knowledge of the anatomy and physiology of the brain!
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