BIO 211 Lecture 22: Bio 211 - Lecture 22
1 Dec 2020
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Document Summary
Forms a liquid cushion that gives buoyancy to the cns organs - 1400 grams but the net weight of the brain suspended in the csf is equivalent to a mass of 25 grams. Mechanical protection serves as a shock absorber. Chemical protection provide optimal environment for proper neuronal function. Circulation allows exchange of nutrients and wastes between blood and brain. Contain cerebrospinal fluid (csf) that is produced by the choroid plexuses. Choroid plexuses are cauliflower like growths of network of capillaries in the walls of the ventricles. Capillaries covered by ependymal cells that form csf from blood plasma by filtration and secretion. Have ion pumps that allow them to alter ion concentrations of the csf. Reabsorption rate is equal to production rate ( ~ 20 ml/hr) Ependymal cells possess tiny hairlike structures called cilia on their surfaces facing the open space of the ventricle cavities they line.
