During the menstrual cycle, the _________ _________ secretes progesterone, which causes the uterine lining to become more vascular and glandular.

Menstrual Cycle

The regular natural change that occurs in the female reproductive system, leading to menstruation and potential fertility.

Progesterone

A hormone produced in the ovaries, placenta, and adrenal glands that plays a key role in the menstrual cycle and maintaining the early stages of pregnancy.

Uterine Lining

refers to the layer of cells lining the uterus, known as the endometrium, which thickens during the menstrual cycle to prepare for potential pregnancy and sheds during menstruation if pregnancy does not occur.