Quiz #4 - CNS - The Circulation of Cerebrospinal fluid (A&P)

1. CSF is produced and secreted by tissue called choroid plexus in all ventricles of the brain.
a. Ependymal cells in the choroid plexus use blood to produce the CSF. They produce and
circulate about 500 mL a day.
b. Motile cilia on ependymal cells create currents that circulate CSF through the ventricles
and other circulatory structures (see flow chart)
2. The brain ventricles
a. Lateral ventricles- 2 large C-shaped spaces in the cerebrum, around the diencephalon.
Anteriorly they are separated only by a thin membrane called the septum pellucidum.
These two are the 1st and 2nd ventricles.
i. Drains into the third ventricles through 2 intervertebral foramina.
b. Third ventricle- fluid filled space inside the diencephalon
i. Drains into the 4th ventricle via the cerebral aqueduct which is a thin tube passing
through the midbrain
c. Fourth ventricle- fluid filled space between the pons, medulla oblongata, and the
cerebellum.
i. Drains into the subarachnoid space around the brain via the L and R lateral apertures
and the median aperture.
ii. Drains into the central canal of the spinal cord
3. CSF Circulation flow chart
4. Hydrocephalus
a. Hydrocephalus is the accumulation of CSF in the CSF circulation.
b. Causes
i. Excess CSF secretion
ii. Slow CSF drainage
iii. Blockage of CSF circulation pathway
c. In newborns can cause the skull to swell and expand.
d. If it develops after skull bones are fused it can cause brain damage due to increased
pressure in the cranial cavity squeezing the brain.