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nicholsz t1_j8td4oa wrote

Yes, blood is toxic to neurons. We have a blood-brain barrier that only lets some things through (either passively if they're small enough like oxygen or alcohol, or actively for bigger molecules).

The brain sits in cerebrospinal fluid (CSF) rather than blood.

As for the actual mechanisms that blood will damage the brain -- first, if you've got a brain bleed, it'll increase intracranial pressure and make it harder for new oxygenated blood to get in, which will kill your neurons from simply lack of oxygen. Second, even a small bleed will kill neurons, because things like the sodium concentration in your CSF will get messed up, and then when the blood dies in your brain it'll leave behind a bunch of iron from hemoglobin which will also kill your neurons.

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AdEnvironmental8339 OP t1_j8u2xk5 wrote

Thanks for your information!

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LoverOfPricklyPear t1_j8v8utt wrote

Well, what they are saying is that blood, and its contents, have some direct detrimental effects, but the most immediate, significant damage is due to secondary effects of all the leaking blood. When blood escapes the vessels, it builds up, and causes pressure to increase within the skull, harming the brain. Also, with the controlled flow of the blood interrupted, the brain does not get the oxygen it needs. These are factors secondary to the blood flow no longer being controlled by vessels.

 

The direct effects of disruption of the blood-brain-barrier (neurons exposed to inappropriate stuff/concentrations of stuff, and products of decomposing RBCs) is indeed damaging, but it is the deprivation of oxygen that has the most, lasting effect. The neurons recover from the damaging, but not so lethal, effects created by the presence of blood, but the secondary lack of oxygen, is what kills the neurons.

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