Plate 13.252 Uterus

Ronald A. Bergman, Ph.D., Adel K. Afifi, M.D., Paul M. Heidger, Jr., Ph.D.
Peer Review Status: Externally Peer Reviewed

The uterine wall undergoes four phases during the menstrual cycle excluding menstruation. These are the (1) resurfacing, (2) proliferative, (3) secretory, and (4) ischemic phases.

The first three phases are shown in this plate. In A, the resurfacing phase, corresponding to days 5 and 6 of the cycle, is shown. During this stage, remnants of the glands in the basal zone of the mucosa proliferate and migrate to cover the raw surface of the endometrium denuded from its mucosa by menstrual flow. The thick myometrium is shown. This is a massive coat of smooth muscle fibers arranged in three concentric layers.

In B, the proliferative or follicular phase of the menstrual cycle, which lasts from day 7 to day 14 of the cycle, is shown. During this stage, the mucosal glands become longer and assume a curved or coiled configuration. The stroma between glands also increases by proliferation of connective tissue cells. The proliferative phase is induced by estrogen (see also Plate 249).

In C, the third or secretory phase, corresponding to days 15 to 27 of the menstrual cycle, is shown. This is also known as the progravid or luteal phase. During this stage, glands stop proliferating and begin to distend and secrete abundantly. in the middle region of the mucosa, saccular outpouchings of the glands are seen. The changes observed in this stage are induced by progesterone following estrogen priming.

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