And again, just like with neural controls, these hormonal controls work by changing vessel resistance and cardiac output.

同样，就像神经控制一样，这些荷尔蒙控制通过改变血管阻力和心输出量来工作。

Behind the scenes are a series of hormonal controls that fine tune the body's internal workings to make menstruation start or stop during those 28 days.

表象之下，这一切都是由人体激素进行调控的，激素精密地控制着身体内部的运作，在这28天里控制经期的起始。