Question

The average menstrual cycle with no fertilization takes how many days?

Answer 1

Hint: The process of reproduction in the human is dependent upon the formation of gametes, and fertilization of the gametes of the male and female. In order to achieve fertilization and reproduction, the body must undertake some specific processes to produce germ cells.

Complete answer:
The regular natural change that occurs in the female reproductive system that prepares it for fertilization, and implantation is known as the menstrual cycle. The cycle aids in production of oocytes and preparation of the uterus for pregnancy.
The menstrual cycle can be divided into three phases which are the follicular phase, ovulatory phase and the luteal phase.

The menstrual cycle typically is a 28 days cycle if there is no fertilization of the egg that leads to pregnancy. In some cases, it can extend up to 33 days. The egg is released from an ovary by the process of ovulation at around day fourteen in the cycle. This is accompanied by other physiological changes in the uterus such as the thickened endometrial lining of the uterus which provides nutrients to an embryo after implantation. However, if pregnancy does not occur and implantation is not required, the hormonal levels falls down which causes breakdown and the lining is released in the form of bleeding known as the menstruation or a "period”

Additional information:
At the beginning of the follicular phase, the levels of different hormones such as estrogen and progesterone are low. The surge in luteinizing hormone and follicle-stimulating hormone levels starts the ovulatory phase. It stimulates the release of the egg from the ovary ovulation, which usually occurs 16 to 32 hours after the surge begins. After the ovulation, the estrogen level decreases during the surge while the progesterone level starts to increase.

During the luteal phase, the levels of luteinizing hormone and follicle-stimulating hormone. The ovary releases the egg from the mature follicle and it forms a corpus luteum. The corpus luteum produces progesterone. As the egg is released and corpus luteum, the estrogen level is high. The increase in the estrogen causes the lining of the uterus to thicken more in order to receive a fertilized egg. In case the egg is not fertilized, the corpus luteum degenerates and no longer produces progesterone. Also, the estrogen level decreases and the top layers of the lining break down and are shed. As the lining is shed menstrual bleeding occurs.

Note: The regular cycle through which the female gamete is produced and the uterus is prepared for fertilization and implantation is called the menstruation cycle. In this process, the egg is released through ovulation by the ovary and the hormonal changes allow the preparation of the endometrium layer to receive implantation. However, if there is no fertilization, the lining of the uterus is shed as menstruation. In this case, the average menstrual cycle takes place in about 28 to 33 days.