PSL300H1 Study Guide - Final Guide: Amacrine Cell, Sleep Induction, Rhodopsin
26 Jan 2013
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Cns = brain (86 billion neurons) + spinal cord (1 billion: protected by bone, meninges, and csf. Meninges = dura mater + arachnoid membrane + pia mater subarachnoid space (sas) contains cerebrospinal fluid (csf) Csf secreted by choroid plexus (specialized regions in walls of ventricles) Ependymal cells transport ions, vitamins, nutrients, water from blood ventricles. Csf cushions brain (mechanical protection) & maintains a chemical env"t w/ ph, [k+], no blood cells, little protein. Flows throughout sas is reabsorbed by arachnoid villi (finger-like projections of arachnoid membrane through dura, into venous sinus) puts into venous blood. Entire volume recycled 3 times per day. Pns = somatic ns + ans: ans includes enteric ns (100-600 million) glia as abundant as neurons, astrocytes help create bbb. Gray matter: dorsal horn (sensory/afferent) = visceral sensory nuclei + somatic sensory n, ventral horn (motor/efferent) = somatic motor n. + autonomic efferent n.
