Question

The end of proliferative phase of menstrual cycle in the human female is immediately followed by

Answer 1

Answer:

The reproductive cycle in the female primates (e.g., monkeys, apes and human beings) is known as a menstrual cycle. 

In human females, menstruation is repeated at an average interval of about 28/29 days and the cycle of events starting from one menstruation till the next one is called as the menstrual cycle. 

One ovum is released (ovulation) during the middle of each menstrual cycle. The major phases of the menstrual cycle are the menstrual phase, follicular phase and the luteal phase. 

The cycle starts with the menstrual phase when menstrual flow occurs and it lasts for 3-5 days. The menstrual flow results due to the breakdown of the endometrial lining of the uterus and its blood vessels. The menstrual phase is followed by the follicular phase and ends with the ovulation around the middle of the menstrual cycle, i.e., 14th day. Thus, the follicular or proliferative phase lasts for 10 to 12 days. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones.

Answer 2

The end of proliferative phase of menstrual cycle in the human female is immediately followed by ovulation.

An overview of the menstrual cycle:

1. Menstruation- low levels of estrogen and progesterone, and leads to shedding of the uterine wall.

2. Follicular phase- rise in estrogen. This continues upto the ovulation phase and prepares an egg for release.

Also includes the proliferative phase- reformation of the uterine lining due to the effect of estrogen.

3. Ovulation- release of a mature egg from the ovary. The egg( also called ovum) bursts from the developed follicle. Estrogen level rises and then falls.

4. Luteal phase- the ruptured follicle forms the corpus lutein that secretes progesterone. This can either lead to pregnancy or luteolysis.