| The final significant changes come during parturition, which is when the uterus prepares itself for labor. The tissues respond to maternal hormonal stimuli for the induction of labor. The uterine myometrium (which is composed of smooth muscle cells) is transformed by a chemical reaction in the smooth muscle, which allows the contraction action. On the surface of the uterus are receptors on the uterine smooth muscle cell membrane. When oxytocin and prostaglandins bind to these receptors, contraction begins. [1] | | | | |