Human

Female

Menstrual Cycle

Menarche = first menstruation period. On average at age 13. (12 to 15, as young as 8.)

Menopause = end of menstrual cycle. Age 45 to 55.

Each cycle lasts 28 days.

Phases of the Menstrual Cycle Each cycle can be divided into three phases based on events in the ovary (ovarian cycle) or in the uterus (uterine cycle).[1]

The ovarian cycle consists of the follicular phase, ovulation, and luteal phase whereas

the uterine cycle is divided into menstruation, proliferative phase, and secretory phase.

ovarian follicle = a roughly spheroid cell set found in the ovaries each has the potential to form an ovum (egg cell) secretes hormones which influence the menstrual cycle A woman at puberty has about 400,000 follicles.

gamete = a cell containing one-half of the DNA for a human. A female gamete is called the egg or ovum. The male gamete is called the sperm. At fertilization the two gametes are merged into a zygote.

The Zygote is the earliest developmental stage of the human embryo. It travels down the oviduct to the uterus and implants itself in the endometrial lining of the uterus.