During the first few days of the menstrual cycle, follicles within the ovary are beginning to mature, and as they do they secrete _____. As the follicles get larger, the levels of this hormone rise, and the endometrium of the uterus responds by _____.

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.