Biology, asked by genius1947, 3 months ago

What do you understand by menstrual cycle? Explain in detail. What are it's four phases? Spam, copied answers from internet are reported. Correct and original answers needed. ​

Answers

Answered by krishna22111970das
4

Answer:

The menstruation cycle refers to the cycles in which a woman’s uterus grows and sheds a lining (the endometrium) which could support the development of a fertilised egg. It typically occurs in 28 day cycles, so a woman generally gets her period every 28 days. However, cycle length may be as short as 21 days or as long as 40 days in some women. The inner lining of the uterus (the endometrium) goes through three phases during the typically 28 day menstrual cycle: the menstrual phase (days 1-5), the proliferative phase (days 6-14) and the secretory phase (days 15-28).

The ovarian cycle, refers to the cycle in which a woman’s ovaries prepare an egg to be released during ovulation. It is divided into two phases: the follicular phase (days 1-14) and the luteal phase (days 15-28), during which different levels of hormones are released. These two cycle occur in a synchronised manner; day 1 of the ovarian cycle is always also day 1 of the menstrual cycle.

Day 1 of the menstrual cycle coincides with the start of a woman’s period (menstrual bleeding) in which the uterus sheds the lining (endometrium) built up in the previous menstrual cycle. The lining of the uterus is regrown during each menstrual cycle. Menstrual bleeding typically continues for 3-5 days in what is known as the menstrual phase of the cycle. Between 50-150ml of blood is released during this period.

After the woman’s period, the proliferative phase of the menstrual cycle begins. The uterine lining is regenerated in preparation for receiving a fertilised egg (should fertilisation occur). The regrowth of the lining each month is needed to create an environment suitable for development of a fertilised egg. If the egg released during ovulation is fertilised and the woman becomes pregnant, the uterine lining stays in place and nourishes the fertilised egg.

If the egg is not fertilised then the menstrual cycle continues for another 14-15 days (the secretory phase). This period is usually the same length, regardless of the total length of the woman’s menstrual cycle. Levels of oestrogen, progesterone, luteinising hormone and follicle stimulating hormone all decline. This causes the blood vessels supplying the uterine lining to deprive the endometrium of the nutrients and oxygen it needs to survive. The cells of the endometrium begin to die and shed, resulting in menstrual bleeding and the commencement of a new menstrual cycle.

As the uterus is preparing its lining in the proliferative phase, the woman’s ovaries are preparing an egg for release. Her oestrogen levels rise stimulating the growth of several ovarian follicles. Each of the follicles contains one egg (oocyte) which matures as the follicle grows. Usually only one follicle (known as the dominant follicle) fully matures and releases the egg it contains. The release of the egg is referred to as ovulation. Rarely a woman will develop and release two or more eggs, and this is when multiple pregnancy occurs (e.g. triplets, depending on the number of eggs released).

In a typical 28 day cycle, ovulation or the release of a mature egg occurs on Day 14, marking the end of the follicular phase. Ovulation will occur earlier in shorter cycles and later in longer cycles. Ovulation occurs when levels of luteinising hormone (a hormone secreted by the pituitary gland in the brain) in the woman’s body rise rapidly. The surge in luteinising hormone signals the ovaries to release the mature egg/s and marks the beginning of the luteal phase of the ovarian cycle. Once released from the ovaries an egg may be fertilised by male sperm, in which case it will be nourished by the uterine lining and establish a pregnancy. Pregnancy changes the woman’s hormonal balance and interrupts the menstrual and ovarian cycles. If the egg is not fertilised it will exit the woman’s body and the ovarian and menstrual cycles continue.

Menstruation Calculator

Menstruation occurs in cycles. The ovaries prepare an egg (oocyte) for release and the womb (uterus) prepares a lining to nourish the egg if it is fertilised. When the egg is not fertilised, the lining of the womb is shed and a woman gets her period (menstrual bleeding).

Menstruation typically occurs in 28 day cycles so most women get their period every 28 days. However, some women have longer cycles and may only get their period every 40 days, while other have shorter menstrual cycles and may get their periods as often as every 21 days.

The menstruation calculator determines when your next period is due based on a 28 day menstrual cycle. All you need to do is enter the date when your last menstrual bleeding began, and the calculator will tell you when to expect your next period.

The four phases are menstruation, follicular, ovulation, and the luteal phase.

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Answered by Anonymous
24

Menstrual Cycle :

The changes occurs in female body every month to be prepare for the pregnancy is called menstrual cycle.

Explanation:

In menstrual cycle, their is expelled of endometrium shed through the blood is known as menstrual cycle. The first menstrual flow is known as menarche. In puberty stage in girls, the eggs of the ovary begins to mature. From the ovary, every month their is a release of matured ovum is called ovulation. Menstrual cycle comes after 28-30 days after one another. The puberty in girls co mes between the age 11-15 years.

Four phases of Menstrual cycle:

  • Menstruation: The vaginal bleeding in women that occurs in a month is called as menstruation.
  • Follicular phase: The half of menstrual cycle is called as follicular phase.
  • Ovulation: From the ovary, every month their is a release of matured ovum is called ovulation.
  • Luteal phase: It is the phase occur after ovulation in which changes of the lining of uterus occurs.

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