Dilates

... So when the words either constriction or dilation are added after the prefix, it specifically indicates that it's the vein that constricts or dilates.

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... drying sensation. Alcohol is commonly wiped onto the skin to reduce a fever (my mother used to do this to me when I was a child). Rubbing alcohol dilates blood vessels when it is massaged vigorously into the skin. This is why sports massage therapists rub down their clients after hard workouts ...

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... the sphincter contracts, causing the pupil to constrict. The dilator muscle runs radially through the iris, like spokes on a wheel. This muscle dilates the eye in dim lighting. The iris is flat and divides the front of the eye (anterior chamber) from the back of the eye (posterior chamber). ...

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