Chapter 12
The Central Nervous System
461
12
The choroid plexus of each ventricle
produces CSF.
1
CSF flows through the ventricles and
into the subarachnoid space via the median
and lateral apertures.
2
CSF flows through the subarachnoid space.
3
CSF is absorbed into the dural venous
sinuses via the arachnoid villi.
4
1
2
3
4
Ependymal
cells
Superior
sagittal sinus
Arachnoid villus
Subarachnoid space
Arachnoid mater
Meningeal dura mater
Periosteal dura mater
Right lateral ventricle
(deep to cut)
Choroid plexus
of fourth ventricle
Central canal
of spinal cord
Choroid plexus
Interventricular
foramen
Third ventricle
Cerebral aqueduct
Lateral aperture
Fourth ventricle
Median aperture
Capillary
Connective
tissue of
pia mater
Wastes and
unnecessary
solutes absorbed
(a)
CSF circulation
Section
of choroid
plexus
(b)
CSF formation by choroid plexuses
Cavity of
ventricle
CSF forms as a filtrate
containing glucose, oxygen,
vitamins, and ions
(Na
+
, Cl
, Mg
2
+
, etc.)
Figure 12.24
Formation, location, and circulation of CSF. (a)
Location and circulatory
pattern of cerebrospinal fluid (CSF). Arrows indicate the direction of flow.
(b)
Each choroid
plexus consists of a knot of porous capillaries surrounded by a single layer of ependymal cells
joined by tight junctions and bearing long cilia. Fluid leaking from porous capillaries is processed
by the ependymal cells to form the CSF in the ventricles.
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