BIO 12 Lecture Notes - Lecture 29: Choroid Plexus, Dura Mater, Arachnoid Mater
14 Sep 2020
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Document Summary
These membranes help to stabilize the neural tissue and protect it from bruising against the bones of the skeleton. This choroid plexus is remarkably similar to the kidney tissue and is consists of capillaries and transporting epithelium derived from the ependyma. This choroid plexus pumps selectively sodium and other solutes from the plasma to the ventricles, creating an osmotic gradient that draws water long with the solutes: this fluid serves two purposes: physical protection and chemical protection. The brain and spinal cord float in the thin layer of fluid between the membranes. The buoyancy of cerebral spinal fluid reduces the weight by almost 30 times. This then causes less pressure on the blood vessels and nerves attached to the cns: there csf also provides protective padding. The choroid plexus is selective (chemical protection) about which substances it transports into the ventricles and as a result, the composition of cerebral spinal fluid is different from the plasma.
