Vesicles to Ventricles Flashcards
ependyma and function
single layer of cells that lines the ventricles. Forms a leaky cell layer to allow exchange of CSF from interstitial space to ventricles.
volume and rate of production of CSF per day
volume = 125 ml. 5oo ml is produced each day
Describe composition of CSF. What happens to the composition of CSF as the ionic composition of plasma changes?
almost no change. composition is very similar to plasma and is tightly regulated.
What produces CSF?
specialized tissues in the ventricles called choroid plexus
How is CSF resorbed by arachnoid granulations?
controversial. either pinocytosis (transcellular vesicle transport) or by hydraulic pressure differences between the CSF and venous sinuses.
non-communicating hydrocephalus and where this happens
flow of CSF is interrupted. obstruction of interventricular foramen or of the cerebral aqueduct.
communicating hydrocephalus
CSF gets to subarachnoid space but isn’t resorbed properly.
brain regions supplied by the anterior circulation system/ICA
anterior half of the brain, including the entire cerebral hemisphere except for the medial part of the occipital lobe and the inferior part of the temporal lobe
brain regions supplied by the posterior circulation system/vertebral arteries
brainstem, cerebellum and some cortex (medial face of the occipital lobe and inferior temporal lobe)
brain regions supplied by the ACA
anterior 2/3s of the MEDIAL face of the cerebral hemisphere, and the orbital cortex
brain regions supplied by the MCA
lateral face of the cerebrum including frontal, parietal and temporal lobes. Also gives off branches that supply the deep white and gray matter of the cerebral cortex.
brain regions supplied by the PCA
medial face of the occipital lobe and the inferior surface of the temporal lobe
brain regions supplied by the PICA
wraps around the medulla and supplies the most caudal part of the cerebellum + choroid plexus of 4th ventricle
brain regions supplied by the AICA
anterior/inferior face of the cerebellum + middle cerebellar peduncle + inferolateral portion of the pons
brain regions supplied by the SCA, superior cerebellar artery
superior half of cerebellum + parts of the midbrain
how do the ventricles communicate with the CSF
2 lateral apertures (foramen of luscka) and caudal aperture. see FA 468.
cisterna magna
cistern located between the cerebellum and dorsal surface of medulla oblongata
cisterns
openings in the subarachnoid space that allow flow of CSF
interpeduncular cistern
wide cavity where the arachnoid extends across between the 2 temporal lobes. Encloses the cerebral peducles and contains the arterial circle of willis.
Describe the relationship between ependymal cells and capillaries in the choroid plexus
In choroid plexus, brain capillaries lose their tight junctions and the ependymal cells acquire tight junctions. Thus solutes diffuse out of capillaries but then must be actively transported across the ependymal cell to get into the CSF (typical epithlial cell transporters: Na/K, Na-proton exchanger, HCO3-Cl, Na-K-Cl)
how is CSF formed by choroid plexus?
fluid is secreted from capillaries adjacent to ependymal cells and actively transported across ependymal cells. This occurs within specialized ependymal cells in the choroid plexus that have tight junctions.
what do the anterior and posterior spinal arteries supply?
rostral part of the spinal cord.
deep structures are drained though inferior sagittal sinus. superficial structures are drained through the superior sagittal sinus.
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