rsn_ at _comcast.net
Wed Jul 23 11:42:40 EST 2003
On Wed, 23 Jul 2003 11:55:30 -0400, Kalman Rubinson <kr4 at nyu.edu>
>On Wed, 23 Jul 2003 11:26:04 -0400, r norman <rsn_ at _comcast.net>
>>On Wed, 23 Jul 2003 10:41:31 -0400, Kalman Rubinson <kr4 at nyu.edu>
>>>On Wed, 23 Jul 2003 03:33:41 -0400, "Mike Dubbeld" <miike at erols.com>
>>>>Yeah, well I am doing it. I send it down then back up my spine. It comes
>>>>as no surprise it is not believable. I learned this from practicing
>>>It's not yoga; it's gravity and hydrostatics.
>>Its not that, either. CSF has the same density as everything else and
>>won't flow by gravity inside a fluid-filled body. Hydrostatics is OK.
>Is pressure equal throughout the CSF circulation and not affected by
>position wrt gravity? I doubt it.
>>I believe the main movement is produced by the slight pressure at
>>which is is produced by the choroid plexus. I have seen claims that
>>respiratory and circulatory movements can influence the flow.
Gravity does work as usual and the pressure varies with height, just
as in the circulatory system. But, also just like the circulatory
system, gravity cannot produce circulation. Under the influence of
gravity, blood would pool in the feet and CSF at the bottom ot the
spinal cord (in upright humans, at least). The closed circulation
must be due to some active, energy-requiring process. So it has got
to be muscle contraction or cilia beating or an increased pressure at
the source (and a decreased pressure at the sink).
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