脑脊液是充满脑室、脑与脊髓蛛网膜下腔的液体,由脑室脉络丛分泌形成。由于血脑屏障的存在,脉络丛在形成脑脊液时,对血浆中各种物质的通过是有选择性的,氯化物、钠、镁、二氧化碳最易通过;白蛋白、葡萄糖、钙、尿素氮等次之;而胆红素、纤维蛋白原等不易通过。因此,脑脊液中的有机成分低于血浆中的有机成分,无机成分相当或高于血浆中的浓度。脑脊液覆盖在脑表面和脊髓周围,它既有缓冲脑部所受的震动,起着机械保护作用;又有参与脑组织的新陈代谢,调节颅内压的作用。脑脊液给脑、脊 Cerebrospinal fluid is full of ventricles, brain and spinal fluid subarachnoid liquid, secreted by the ventricular choroid plexus. Due to the presence of the blood-brain barrier, choroid plexus is selective for the passage of various substances in the plasma during the formation of cerebrospinal fluid. Chloride, sodium, magnesium and carbon dioxide are most easily passed; albumin, glucose, calcium, urea nitrogen, etc. Followed by; and bilirubin, fibrinogen and other difficult to pass. Therefore, the organic components in CSF are lower than the organic components in plasma, and the inorganic components are comparable to or higher than those in plasma. Cerebrospinal fluid covers the surface of the brain and around the spinal cord, which not only buffered the vibration suffered by the brain, plays a mechanical protective effect; also participate in brain metabolism, regulate the role of intracranial pressure. Cerebrospinal fluid to the brain, ridge