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Alcohol & Vertigo
The cupula has its own blood supply,
whereas the endolymph is made by
cells which pull fluid from the
bloodstream and secrete it into the
canals. When someone drinks alcohol,
it is absorbed into the blood,
making it more dilute, or less dense
(lower specific gravity) than usual.
Now imagine, for instance, the
horizontal semicircular canal
sitting in the inner ear. As our
overindulgent imbiber lays down in
the barcolounger, the canal becomes
oriented such that the cupula is
about at 3 o'clock. The cupula,
which is surrounded by endolymph
(most of which was made prior to the
first drink) is filled with the
dilute blood. Normally, the cupula
is neither heavier nor lighter than
the endolymph, and doesn't try rise
or sink. But now, with less dense b
lood inside, it floats up in the
more dense endolymph, deflecting the
cupula as during head rotation, and
causing the same signal change in
the nerve to the brain, which it
incorrectly interprets as a spinning
motion. But our unfortunate reveler
is not o ut of the woods yet. The
endolymph produced while under the
influence is itself influenced by
the specific gravity of the blood
when it was made. Several hours
after the bars close, and the first
bout of spinning is over, the blood
is back to its normal specific
gravity, or even a bit more dense if
the drinker is, as is often the
case, a bit dehydrated. The
endolymph, however, is a little less
dense than usual, reflecting the
state of the dilute blood when it
was made. So now the cupula will
sink in t he endolymph, and the
spinning, although perceived in the
opposite direction as before, is
back until blood and endolymph again
become equilibrated to their normal
specific gravity.
Content Courtesy :
www.bme.jhu.edu
Note : Information herein is
provided for informational purposes
only and is not a substitute for
professional medical advice. You
should not use this information for
diagnosing or treating a medical or
health condition. If you have or
suspect you have a medical problem,
promptly contact your professional
healthcare provider. Please consult
your healthcare provider before
beginning any course of
supplementation or treatment.
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