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Fascinating! As someone not familiar with how the lymph system operates, do you care to explain how muscle contractions outside the brain cause the lymph system
by voisin 6y ago
Fascinating! As someone not familiar with how the lymph system operates, do you care to explain how muscle contractions outside the brain cause the lymph system in the brain to expel waste? I understood the blood-brain barrier sort of insulated the brain from a lot of this kind of thing.
- throwaway5752 6y agoLymph is fascinating. It is your other circulatory system. Capillaries are are so narrow they can only allow a single erythrocyte through at the same time. The pressure from your heart causes fluid leakage from the thin vessels. Lymph ducts/nodes help get this fluid back into your blood. Since the heart doesn't pump lymph, that helps move it through your body is actually your musculoskeletal system. That is to a certain degree true from your venous / return flow in your "normal" circulatory system, too. It's why your feet can swell if you're sitting down too much. I'd speculate that lymphatic flow efficiency has local and systemic elements that contribute to it (and so your leg muscles moving lymph help your overall lymphatic system health).
- plutonorm 6y agoThis didn't answer the question, like at all!
- throwaway5752 6y ago"I'd speculate that lymphatic flow efficiency has local and systemic elements that contribute to it (and so your leg muscles moving lymph help your overall lymphatic system health)." Lymph system helps clear waste / ISF from the brain. Overall lymphatic circulation improvement from increased activity would intuitively improve lymphatic clearance from the brain. That would be true if there was direct lymphatic clearance or some indirectly / osmotic gradient driven process (I don't know which, or neither, is the case).
- jjtheblunt 6y agoI'm no expert, but if the lymphatic system's flow is driven by the motion in its surroundings because the muscles and skeleton are in motion, maybe drainage just happens via gravity if motion continually alters momentum and gravity vectors? Genuinely curious too...
- hinkley 6y agoAm I remembering it incorrectly or did someone recently discover a mechanism for lymph to move through connective tissues (in particular, ligaments)?
- ford_o 6y agoIs it just about muscular contraction, or does any kind of motion have positive effect on the lymph system? Say a rollercoaster or jumping on trampoline.
- DoreenMichele 6y agoI'm not sure anyone knows the answer to that in specific. In my experience, exercise is often followed by a nap and my inference is that clearing lymph from other tissues somehow encourages the body to also clear lymph from the brain, but I haven't actually found an explanation for how that works. You might find this general overview of the body's lymphatic system interesting: https://news.ycombinator.com/item?id=25427090 https://news.ycombinator.com/item?id=25427090
- 1e-9 6y agoAs noted by the article, it was only recently discovered that the central nervous system had lymphatic drainage (see [1]). I’m simply connecting the results of this mouse study with what we know about the lymphatic system, skeletal muscle, and the apparent benefit of exercise on Alzheimer’s disease risk, to form a hypothesis. I strongly suspect it’s true, but I cannot represent it as fact. Edit: Here is a more direct answer to your question: 1) Increased localized pressure from contracting muscle pushes lymph away through a vessel. 2) Reduced localized pressure from relaxing muscle allows new lymph to refill the evacuated vessel portion. 3) Lymphatic vessels have valves that keep all this flow moving in the same direction. 4) Given that the lymphatic system is connected to the central nervous system, increased muscular contraction could increase drainage of the brain. [1] https://www.nature.com/articles/nature14432 https://www.nature.com/articles/nature14432