During the final stages of human gestation, receptors for the hormone oxytocin increase on the smooth muscle cells of the uterus. the release of oxytocin during labor stimulates the smooth muscle tissue in the wall of the uterus. the vigorous contraction of the uterine smooth muscle push the baby through the birth canal so that delivery can occur. this process involves the interaction of which organ systems? * endocrine and muscular only endocrine and reproductive only endocrine, muscular, and reproductive endocrine, reproductive, and excretory