الأربعاء، 20 يناير 2010

Does the inner ear help regulate blood pressure?


The ear has three general anatomical areas - the outer conductive portion, the middle transmissive small bones area, and the inner ear with its neural connections and semicircular canals.  The obvious function of the inner ear is for the maintenance of balance, with the three x/y/z-axis oriented canals and the otoliths serving that purpose.

Now researchers at Harvard Medical School working with NASA have suggested that the inner ear also may play a role in the regulation of blood pressure.  It's a fascinating concept, and quite logical.  Blood pressure needs to be adjusted every time the body goes from a supine/recumbent position to an upright one, because more pressure is required to lift blood from the chest to the brain in the vertical position.  Since the inner ear monitors that position, it may also send the signals for the heart and vasculature to alter their contractility to maintain intravascular pressures at adequate levels.

Failure of autoregulation in this regard may lead to orthostatic hypotension (low pressure when standing up).   One wonders whether malfunction in the other direction might contribute to hypertension in some individuals, though the researchers do not speculate in this regard.  More detaiils at the BBC.

Image credit.

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