Ventricular system Flashcards
Cerebrospinal fluid has a number of functions in the CNS
protects brain from mechanical damage
regulates fluid composition around neurons
provides endocrine/ paracrine pathways for non-neuronal signaling
Regulates fluid composition around neurons
Contributes to ion homeostasis for optimal neural signaling
Maintains low protein environment in CNS, limits proliferation (helps keep tumors down), preserves neural connectivity
the essence of the blood-CSF barrier
tight junctions of the choroid plexus epithelial cells
Glymphatic System
Helps move cellular waste into venous drainage system of deep brain parenchyma
The brain doesn’t stop consuming energy when asleep. The glymphatic system is 10X more active asleep than when we’re awake
What maintains fluild homeostasis in the brain?
Blood, CSF and ISF have to all work concurrently to maintain fluid homeostasis in the brain
CSF is created in the choroid plexus
Choroid plexus is a single layer of ependymal cells overlaid with a layer of pia.
Fenestrated choroidal capillaries allow macromolecules and ions to flow from the blood into extracellular space
Choroid epithelial cells contain tight junctions, prevent the diffusion of molecules into the brain
what provides blood for the choroidal plexus?
the choroid artery
Histology of the choroid epithelium
Single layered cuboidal epithelium Tight Junctions Luminal (apical) side has Cilia Aquaporin 1 channels
Describing how CSF is derived from blood
fenestrated capillary
active transporters through the epithelium
becomes high sodium, low potassium to allow action potentials to work well. (sodium rushes in…; potassium needs to leave the neurons. directly related to action potential synthesis)
areas where the CSF enters the subarachnoid space
median aperture (foramen of magendie)
lateral apertures (foramina of Luschka)
Naming the ventricles: Lateral Horns
Frontal Horn: In frontal lobe Central part/body: In frontal and parietal lobes, extends to splenium Occipital horn: into occipital lobe Temporal horn: into temporal lobe Atrium: around splenium
Naming the ventricles: Third Ventricle
Looks like an oddly shaped doughnut (hole is the interthalamic adhesion)
Divides the thalamus and the hypothalamus
Contains 4 recesses: Optic top beak Infundibular- bottom beak Pineal Suprapineal
Naming the ventricles: Fourth Ventricle
makes a nice diamond shape.
At the level of pons and medulla
Roof is:
Superior Medullary Velum
Inferior Medullary Vellum
3 apertures that allow for CSF to flow into the subarachnoid space of rest of brain
- 2 Lateral (Foramina of Luschka)
- 1 Medial (Foramen of Magendie)
** main output system to get out of the ventricular system and into the rest of the brain
AQP1 and AQp4
both important for CSF flow, regulating fluid homeostasis.
AQP4 is in the astrocytic end feet
Ventricular system overview:
Lateral ventricles --> interventricular foramina--> 3rd ventricle--> cerebral aqueduct--> IV ventricle --> central canal OR Lushka, Magendie, Luschka
