【吸收压】脑脊液的吸收率取决于脑脊液压力的高低,并在相当宽的生理范围内呈相对的线性关系。当脑脊液压力增高时,脑脊液的吸收阻力降低,其原因可能为在低压时不出现的开放通道有关。Weed 提出,除了压力因素外,还与吸收部位的半透膜胶体渗透压增高有关,但后来的生理学研究并未证实胶体渗透压增高的存在。有人提出构成静脉窦壁的蛛网膜内皮细胞的胞饮受到压力的影响,但其过程并不取决于代谢的变化,唯一被证实与脑脊液吸收有关的为脑脊液的液压梯度。【蛛网膜绒毛的吸收】蛛网膜绒毛能从蛛网膜下腔将脑脊液吸收到大的静脉窦,它具有从蛛网膜下腔突入到静脉窦侧隐窝的细胞丛。电镜观察表明,这种绒毛被一层紧密连接的内皮细胞所覆盖,并与静脉窦的内表面相接续。这些绒毛肉眼可见者被称为蛛网膜 Absorption pressure Cerebrospinal fluid absorption rate depends on the level of cerebrospinal fluid pressure, and in a relatively wide range of physiological showed a relatively linear relationship. As cerebrospinal fluid pressure increases, CSF resistance decreases, probably due to open channels that do not appear at low pressures. Weed suggested that in addition to the stress factor, the osmotic pressure of the semipermeable membrane colloid at the site of absorption was also increased, but subsequent physiological studies did not confirm the existence of increased colloid osmotic pressure. It has been proposed that the aorta endothelial cells that make up the sinus wall are affected by pressure, but the process does not depend on metabolic changes. The only fluid gradient that is associated with cerebrospinal fluid absorption is cerebrospinal fluid. [Absorption of arachnoid villi] Arachnoid villi can absorb cerebrospinal fluid from the subarachnoid space into the large venous sinus, which has a cluster of cells protruding from the subarachnoid space into the sinuses lateral crypt. Electron microscopy showed that the villi were covered by a layer of closely linked endothelial cells and continued to the inner surface of the sinus. Visually, these villi are called arachnoid