The middle thick layer of smooth muscles in the wall of the uterus is

The wall of the uterus has three layers of tissue. The external thin membranous perimetrium, middle thick layer of smooth muscle, myometrium and an inner glandular layer called endometrium that lines the uterine cavity. The endometrium undergoes cyclical changes during the menstrual cycle while the myometrium exhibits strong contraction during delivery of the baby.