Lymphatic drainage of the brain

Published on September 28, 2023   29 min

A selection of talks on Physiology & Anatomy

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My name is Roxana Carare. I'm a professor of clinical neuroanatomy in the University of Southampton in the UK, and my area of expertise is the drainage of fluids from the brain. Today I'm going to be talking to you about the lymphatic drainage of the brain.
Every other organ in the body apart from the brain has traditional lymphatic vessels, so these are large diameter vessels that collect fluid and waste metabolites and cells from the tissues to return them to the venous system. The brain and the eye do not have traditional lymphatic vessels, so in order to better understand what the lymphatic drainage of the brain is like, we need to recap and consider what fluids exist within the skull.
In the skull is the brain parenchyma, and there are three fluids, one is blood, another one is cerebrospinal fluid, and the third one is the interstitial fluid that occupies the spaces between the cells, so the extracellular spaces. The major mechanisms of clearance of fluid and solutes from the CNS are by absorption into the blood or by drainage of the cerebrospinal fluid to the blood and lymph nodes, and then again to the blood. The interstitial fluid drains to lymph nodes and to the blood. There is also uptake of solutes by cells of the CNS, of the central nervous system, for example, by microglia or astrocytes and that leads to intracellular degradation. Or there can be enzymatic degradation of extracellular solutes within the brain parenchyma tissue.