CSF & Hydrocephalus Flashcards
CSF is produced primarily by?
Choroid Plexus
Choroid plexus is found in?
- Lateral ventricle (majority- 65%) *
- Third ventricle
- Fourth ventricle
– Consists of villous folds lined by epithelium with a central core of highly vascularized connective tissue
– Specialized layer of ? cells = choroidal epithelium overlies these
villi
Choroid Plexus
- ependymal
BBB
1. Continuous ? junctions
- ? provides structural support
- ? necessary for BBB development
- Transport carriers for ? and essential amino acids
- ? ion transporters
- Metabolic processes within the ? cells control entry of neurotransmitters
- Tight **
- Basement membrane
- Astrocytic foot processes
- Glucose
- Sodium
- Endothelial
Blood-CSF Barrier
- Separates the CSF and blood
- Restricts the passage of substances
- More or less permeable than the blood-brain barrier?
- Impairment in the blood-CSF barrier leads
to an increase in ? concentration in
the CSF
- More
- Protein
Blood-CSF Barrier
- ? cells are interconnected by tight junctions
Choroid cells **
CSF takes 2 steps to form
Filtration and active transport
How do plasma and CSF compare?
It differs in quantity not quality
Ex. Plasma protein is 7000 and CSF is 20
Test for CSF composition by lumbar puncture between ? and ?
L4 and L5
Functions of CSF
- Protection: “shock absorber”
– Protects brain from damage by “buffering”
the brain
– Protects from sudden pressure or
temperature changes
- Buoyancy
– Brain is immersed in fluid, the net weight is reduced from 1,400 gm to about 50 gm
– Pressure at the base of the brain is reduced *** - Metabolic
– One-way flow of CSF to the blood takes
potentially harmful metabolites, drugs, and
other substances away from the brain - Endocrine Medium for the Brain
– CSF serves to transport hormones to other
areas of the brain
What are the cavities inside the brain?
- Paired lateral ventricles
- 3rd ventricle
- Cerebral aqueduct
- 4th ventricle
What leaves the 4th ventricle?
- 2 lateral foramina (Luschka)
- 1 medial foramen (Magendie)
Flow of CSF
- Lateral Ventricle
- Through interventricular foramen of Monroe
- Third ventricle
- Cerebral aqueduct
- Down to the Fourth Ventricle between pons and cerebellum
- Goes to subarachnoid space via the 2 lateral and 1 medial aperture besides going to the central canal
- Through the arachnoid villi, absorbed from subarachnoid space to sagittal sinus
When ? is higher than ?, it will flow to the sagittal sinus
- CSF
- Venous pressure
(it will never flow backwards!)
Disorder in which an excessive amount of cerebrospinal fluid (CSF) accumulates
within the cerebral ventricles and/or subarachnoid spaces, resulting in ventricular
dilation and increased intracranial pressure (ICP)
- can be congenital or aquired
Hydrocephalus
Hydrocephalus:
- May be due to: ?
■ Overproduction of CSF (rare)
■ Under-absorption of CSF (at the level of the arachnoid villi)
■ Obstruction of the outflow of CSF from the ventricles
2 types of Hydrocephalus
- Communicating (or non-obstructive)
2. Non-communicating (or obstructive)
Communicating Hydrocephalus:
- Flow of CSF is blocked (before or after?) it exits the ventricles
- Due to abnormalities that inhibit the resorption of CSF, most often at the level of the ?
- Typically associated with (increased or decreased?) ICP
- AFTER
- arachnoid villi
- increased
- Condition of pathologically enlarged ventricular size
- Characterized by: enlarged cerebral ventricles with intermittent elevated CSF pressure on lumbar puncture
- Most common in adults over 60
Normal Pressure Hydrocephalus
- Chronic Communicating Hydrocephalus