Ⅰ.CSF colorless, watery lipuid 약 140 ml ( ⑴ 생성 ㉮ 4개의 ventricles (2 lateral, 3rd and 4th ventricles)의 choroid plexus (70%) ㉯ Braion metabolic products 의 capillary ultrafiltration ( 30%) Choroid plexus :