Final answer:
The endometrium of the uterus is the organ shed during the menstrual cycle, specifically during menstruation. This process is part of the uterine cycle which prepares the uterus for potential pregnancy and is regulated by hormones.
Step-by-step explanation:
The organ that is shed during the menstrual cycle is part of the uterus, specifically the endometrium. The menstrual cycle proceeds in several phases: the menses phase or menstruation, the proliferative phase, and the secretory phase. The menstruation phase involves the shedding of the endometrial lining of the uterus, which includes blood and tissues. If fertilization of an egg does not occur, this lining is not needed to support a pregnancy, and thus, it is expelled from the body, resulting in blood flow known as the menstrual period or menses. This shedding marks the start of a new menstrual cycle, which is necessary for reproductive health and preparation for potential pregnancy.
The menstrual cycle is controlled by hormones from the hypothalamus, the pituitary gland, and the ovaries. As the egg and follicle develop in the one of the ovaries, the uterus prepares for potential pregnancy by thickening its lining. Without fertilization, the uterus will shed this lining during menstruation, and the cycle begins anew.