Cerebrospinal Fluid
What is internal hydrocephalus?
"water on the brain" - Excess of CSF in lateral and 3rd ventricles beacuse drainage is blocked. can't get out of ventricles to the subarachnoid space
What is the flow of CSF?
1) Lateral ventricles (1 and 2) 2) Interventricular foramen 3) 3rd Ventricle 4) cerebral aqueduct 5) 4th ventricle - to several locations: subarachnoid space in spinal cord, brain, and central canal
What is external hydrocephalus?
CSF can't get out of subarachnoid space, failure of cerebrospinal fluid to be reabsorbed into the bloodstream from the subarachnoid space
What is freely permeable except for at the choroid plexus?
Ependymal lining
What is the blood-brain barrier?
The brain is protected from harmful chemicals in the blood stream by thicker walls surrounding the brain's blood vessels. protects from systemic circulation, brain needs glucose, decreased glucose can result in dizziness, confusion, coma & death
What is cerebrospinal fluid?
completely surrounds and bathes the surfaces of the CNS
What easily crosses the blood brain barrier?
glucose, O2, sodium pentothal, chlorome pentothal, tetracycline, some antibiotics, some ions, Na+, lipid soluble, truth serum, nicotine, alcohol, heroin
What is the choroid plexus?
highly vascular portion of the lining of the ventricles that secrete CSF. Combo of ependymal cells and highly permeable capillaries. Floors of lateral ventricles, roof of 3rd and 4th ventricles
What crosses the blood-brain barrier with help?
membrane proteins, urea, Cl-, insulin, sucrose, some amino acids
What doesn't cross the blood brain barrier at all?
most proteins and antibiotics
What are the functions of cerebrospinal fluid?
prevent contact between delicate neural structures and the surrounding bones, act a shock absorber, support the brain, transport nutrients, chemical messengers and waste products, constant communication with interstitial fluid of CNS
Where is the home of CSF?
subarachnoid space - projections into sup sag sinus
What are arachnoid villi?
villi found in the superior saggital sinus which reabsorb CSF
