Final answer:
Estrogen and progesterone are the key hormones that stimulate the growth of the functional layer of the endometrium, with their levels rising after ovulation to prepare the uterus for a possible pregnancy.
Step-by-step explanation:
The hormones that influence the growth of the functional layer of the endometrium are primarily estrogen and progesterone. During the menstrual cycle, specifically in the follicular phase, estrogen is released from developing follicles which aids in endometrial regrowth and prepares the uterus for a potential pregnancy. Following ovulation in the luteal phase, if fertilization occurs, progesterone produced by the corpus luteum stimulates the production of decidual cells of the endometrium that nourish the blastocyst before placentation. Even if fertilization does not occur, progesterone helps thicken the endometrial lining, creating a conducive environment for implantation. The functional layer of the endometrium thickens in response to these hormones, particularly after ovulation when their concentrations increase.