Cov ntshav ncig thoob plaws hauv lub cev, muab cov khoom noj txhua qhov chaw thiab tshem tawm cov khoom pov tseg, yog li nws yuav tsum tau tswj xyuas raws li qhov xwm txheej.Txawm li cas los xij, thaum cov hlab ntsha raug mob thiab tawg, lub cev yuav tsim cov tshuaj tiv thaiv, suav nrog vasoconstriction ...
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