Cranium, Ventricles, Meninges (Lecture #5) Flashcards
what part of the brain rests in the anterior cranial fossa
inferior surface of the frontal lobes (orbital gyri)
frontal poles contact the anterior border of the anterior cranial fossa
what part of the brain rests in the middle cranial fossa
inferior surface of the temporal lobes
temporal poles in contact with anterior border of middle cranial fossa
what part of the brain rests in the posterior cranial fossa
inferior surface of the cerebellum
what part of the skull does the pons rest on
clivus
what makes up the roof of the posterior cranial fossa
tentorium cerebelli
what lobes of the brain do not rest in the floor of a cranial fossa
occipital
parietal
meninges
pia
arachnoid
dura
pia mater
very thin
closely adherent to brain
follows gyri and sulci
subarachnoid space filled with
CSF
what travels thru subarachnoid space
major arteries
cranial nerves
cortical veins
arachnoid mater
wispy projections down into subarachnoid space
arachnoid granulations project from here into dural venous sinuses
what travels through subdural space
bridging veins
arachnoid granulations
9both going to dural venous sinuses)
dura mater
double-layered membrane
occasionally these layers split to form dural venous sinuses
what makes up the falx and tentorium cerebelli
inner layer of dura mater
epidural space
forms periosteum of skull (closely adherent)
what travels through epidural space
meningeal arteries
what does the lumbar cistern contain
CSF
where fluid is obtained in LP
supratentorial
describes intracranial nervous tissue above the tentorium cerebelli
infratentorial
describes intracranial nervous tissue below the tentorium cerebelli
venous draining pattern in brain
- small veins within brain
- cortical surface veins in subarachnoid space
- bridging veins in subdural space
- dural sinuses
- internal jugular vein
locations of dural venous sinuses
- where falx attaches to top of skull
- bottom of the falx
- where tentorium attaches to skull
possible problems in venous system of brain
rupture of bridging veins
great cerebral vein (of Galen) can have a congenital aneurysm
infection in face/nasal sinuses can spread to venous sinuses
CSF produced by
specialized leaky arterial blood vessels within ventricles (choroid plexus)
CSF contains
water
protein
glucose
occasionally WBCs
flow of CSF
- lateral ventricles
- 3rd ventricle
- 4th ventricle
- squirts out holes in 4th ventricle into subarachnoid space
- absorbed by arachnoid granulations
- dumped back into blood stream via dural venous sinuses
function of CSF
provides a cushion of fluid for brain and spinal cord
washes out waste and toxins
blood brain barrier
capillaries in the brain have cell linings that are very close together
prevents “bad” things in blood from getting to brain
keeps fluctuations in electrolytes from occurring so neurons can function optimally
what can cross the blood brain barrier
meds that cause hyperactivity or hallucinations
alcohol, LSD
circumventricular organs
areas of brain where there is no blood brain barrier
examples of circumventricular organs
neurophpophysis/median eminence area postrema (AKA: CTZ)- vomit center