BRAIN VENTRICLES AND CEREBROSPINAL FLUID

BRAIN VENTRICLES

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Lateral ventricles (First and Second)

• The lateral ventricles are the largest ventricles
• Extend into cerebral hemispheres
• Occupy parts of the frontal, temporal, and occipital lobes

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THE THIRD VENTRICLE

• Third ventricle is midline of the brain
• Beneath the corpus callosum
• Communicates with lateral ventricles
• Communication through interventricular foramina

THE FOURTH VENTRICLE

• In brainstem anterior to cerebellum
• Cerebral aqueduct connects it to third
• Continuous with central canal of spinal cord
• Has openings in its roof
• Openings lead to subarachnoid space of meninges

CEREBROSPINAL FLUID

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CEREBROSPINAL FLUID

• Secreted from choroid plexuses
• Formed in lateral venticles
• Circulates in third and fourth ventricles
• Reabsorbed into the blood
• Completely surrounds brain and spinal cord

CEREBROSPINAL FLUID CONTINUED

• Occupies subarachnoid space of meninges
• Supports and protects the organs
• Absorbs forces that might jar or damage them
• Maintains stable ionic concentration in CNS
• Provides a pathway to blood for wastes

OTHER INFORMATION

• Fluid pressure in ventricles normally constant
• C.F. secreted and reabsorbed continuously and equal rates
• Infection, tumor, or blood clots can interfere with circulation
• A lumbar puncture (spinal tap) measures pressure of C.F.