PSYC 211 Chapter Notes - Chapter 3: Dura Mater, Superior Sagittal Sinus, Pia Mater
8 Sep 2016
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Meninges x meninges (singular: meninx) tissue that encase the central nervous system: the dura mater, arachnoid membrane, and pia mater. Because the brain is completely immersed in liquid, its net weight is reduced to approximately 80 g; thus, pressure on the base of the brain is considerably diminished. Its walls divide the surrounding part of the brain into symmetrical halves. Cerebrospinal fluid is extracted from the blood and resembles blood plasma in its composition. Csf is man- ufactured by special tissue with an especially rich blood supply called the choroid plexus, which protrudes into all four of the ventricles. The flow of csf is interrupted at some point in its route of passage. For example, a brain tumor growing in the midbrain may push against the cerebral aqueduct, blocking its flow, or an infant may be born with a cerebral aqueduct that is too small to accommodate a normal flow of csf.
