3- ventricles Flashcards
What is the somatosensory cortex located in?
Does it matter whether you are in foot or hand region of somatosensory cortex in terms of internal carotid artery flow
postcentral sulcus in the superior/anterior parietal lobe
YES
foot region close to sagittal midline served by anterior cerebral artery
hand region more lateral in area served by middle cerebral artery
pathway of internal carotid to internal jugular in foot region
internal carotid anterior cerebral somatosensory cortex superior sagittal sinus confluence of sinuses transverse sinus sigmoid sinus internal jugular vein
pathway of intenral carotid to internal jugular in hand region
internal carotid middle cerebral somatosensory cortex superior sagittal sinus confluence of sinuses transverse sinus sigmoid sinus internal jugular vein
How would blood from left vertebral artery reach frontal lobe of right side if blocked internal carotid
left vertebral basilar right posterior cerebral right posterior communicating right internal carotid right middle cerebral or anterior cerebral
know the components of circle of willis
see page 7 of objectives
what is the order of the meninges
inside --> out pia arachnoid dura PAD
what is pia mater composed of
what about arachnoid
what about dura
what fillls the arachnoid space
pia = single layer of cells
arachnoid = loose spongy layer (filamentous surface of brain to dura)
dura = leathery layer and hangs loosely in spinal column
CSF fluid
trace path of CSF from lateral ventricles to reabsorption in archnoid granulations
lateral ventricle
foramen of Monro (interventricular foramen)
third ventricle
aqueduct of Sylvius (cerebral aqueduct)
fourth ventricle
subarachnoid space via 3 cisterns (two lateral, one caudal)
flows around subarachnoid space
arachnoid granulations.
Be able to identify on MRI images, CAT scans and sections through the brain:
lateral ventricle,
third ventricle,
fourth ventricle,
interventricular foramen (foramen of Monro),
cerebral aqueduct (aqueduct of Sylvius),
cisterna magna,
interpeduncular cistern.
interpeducular cistern = cavity where arachnoid mater extends btwn temporal lobes
contains CSF and cerebral peduncles and Circle of Willis
btwn 3rd ventricle and pons
Describe ependymal cells vs. choroid plexu
ependymal = inside of ventricles to form leaky barrier MOST of time
plexus = specialized areas of ependymal cells in lateral ventricles making CSF
difference btwn ependymal and endothelial cell functions in brain vs. choroid plexus
brain = leaky ependymal + tight endothelial
plexus = tight ependymal + leaky endothelial
so in plexus ependymal cells can access blood contents but also perform active transport (CSF comes from plasma thru endothelial junctions)
what volume and rate of production of CSF
volume = 500 mL/day
but volume at any time = 125 mL in ventricle + subarachnoid space
25 mL in ventricle
100/125 in subarachnoid spaceso fill and empty CSF system 4 times per day
What happens to composition of CSF as ionic composition of plasma changes
fluctations in plasma ion concentrations = LITTLE TO NO EFFECT ON ION CONCENTRATION IN CSF
ex: incr plasma K+ 3 mM = no change CSF K+ b/c if changed then get epilepsy
what in general causes hydrocephalus
when CSF can’t flow from lateral ventricles or subarach space or failure in resorb CSF
incr intracranial pressure
compress brain
Difference btwn noncomm vs comm hydrocephalus
noncomm = CSF block by obstruction of interventricular foramen or cerebral aqueduct
comm = CSF gets to subarach space but not reabsorb
