The endometrial lining is vascularized by:

Explanation

Estrogen, a hormone produced mainly by the ovaries, does influence the menstrual cycle and the endometrial lining in several ways. During the menstrual cycle, rising levels of estrogen stimulate the growth and proliferation of the endometrial cells, causing the endometrium to thicken. This is part of the preparation for a potential pregnancy. Estrogen also contributes to the development of a rich network of blood vessels within the endometrium. The increased vascularity is important for supplying nutrients and oxygen to the growing endometrial tissue. However, while estrogen supports the conditions that are favorable for vascularization, it is not the direct cause of the blood vessel formation itself.