How the central nervous system maintains tight control of extracellular conditions has been a fundamental question in neuroscience until recent discovery of the glial-lymphatic, or glymphatic, system was made this past decade. Lymphatic vessels serve as collectors of this fluid in most organs however, these vessels are absent in the central nervous system.
![interstital fluid image interstital fluid image](https://tarbell-lab.ccny.cuny.edu/wordpress/wp-content/uploads/2014/07/interstitial-flow-fig10.png)
Normal physiologic function of organs requires a circulation of interstitial fluid to deliver nutrients and clear cellular waste products.
![interstital fluid image interstital fluid image](https://image5.slideserve.com/9635501/interstitial-fluid-fluid-between-cells-derived-l.jpg)