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प्रश्न
What is the menstrual cycle?
Briefly describe the menstrual cycle.
उत्तर १
Female reproductive system undergoes some changes (that prepare the uterus for pregnancy) at puberty and those changes repeat at an interval of every 28-30 days. Such repetitive changes are called the menstrual cycle.
उत्तर २
The beginning of the menstrual cycle marks the onset of puberty in human females. Menstruation occurs if an ovum released by the ovary of a woman is not fertilized during ovulation. This is described below.
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When a girl reaches puberty at the age of about 10, the sex hormones released into her blood cause some of the ova (or egg cells) in her ovaries to become mature (or ripe).
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Usually, one mature ovum (or egg) is released off (jm one of the ovaries into the oviduct once every 28 days. This is called ovulation.
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Before ovulation (or release of ovum), the inner wall of the uterus becomes thick and spongy, and full of tiny blood vessels to receive the fertilized ovum.
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If the ovum does not get fertilized then the thick and soft inner lining of the uterus breaks. So, the thick and soft inner lining of the uterus along with the blood vessels and the dead ovum comes out of the vagina in the form of bleeding called menstruation.
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Menstruation usually occurs 14 days after ovulation and usually lasts for about 3 to 5 days.
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After menstruation is over, the inner lining of the uterus starts building up again so that it may become ready to receive the next ovum.
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If the ovum does not get fertilized even now, then menstruation takes place again. This cycle of menstruation is repeated again and again in women after every 28 days. The menstrual cycle is controlled by hormones.
Menstruation stops temporarily when the ovum gets fertilized and the woman gets pregnant. Menstruation also stops due to nutritional deficiencies, low body weight, stress, eating disorders, excessive weight gain, etc.
संबंधित प्रश्न
Describe the roles of pituitary and ovarian hormones during the menstrual cycle in a human female.
Explain the role of pituitary and the ovarian hormones in menstrual cycle in human females
Identify True/False statement. Correct false statement to make it true.
Menstrual cycle ceases during pregnancy.
the Biological/technical term for Complete stoppage of menstrual cycle in females
Explain menstrual cycle in human females.
Explain the ovarian and uterine events that occur during a menstrual cycle in a human female under the influence of pituitary and ovarian hormones respectively.
Observe the figure and answer the questions given below.
a) What does the above figure indicate?
b) Which human organs are involved in this process?
c) Name the hormones responsible for this process.
d) After how many days these repetitive changes take place?
e) ‚A woman should stay away from others, as her body is impure during this process.‛ What is your opinion about this statement? Elaborate it.
Read the following passage and answer the question that follows:
Rahini and her parents were watching a television programme. An advertisement flashed on the screen which was promoting the use of sanitary napkins. Rahini’s parents suddenly changed the channel, but she objected to her parents and explained the need and importance of such an advertisement.
What is first menstruation called? When does it occur?
Read the following passage and answer the question that follows:
Rahini and her parents were watching a television program. An advertisement flashed on the screen which was promoting the use of sanitary napkins. Rahini’s parents suddenly changed the channel, but she objected to her parents and explained the need and importance of such an advertisement.
Do you think that Rahini’s objection towards her parents was correct? If so, Why?
Progesterone peaks during which phase of the menstrual cycle?
Match the Columns.
| Column I | Column II | ||
| i. | Proliferative phase | a. | Breakdown of the endometrial lining |
| ii. | Secretory phase | b. | Follicular phase |
| iii. | Menstruation | c. | Luteal phase |
The temporary endocrine gland in humans is ______.
On the fourteenth day of the menstrual cycle the female gamete released is _____.
The mammalian corpus luteum produces ______.
Secretion of progesterone by corpus luteum is initiated by ______.
Which set is similar?
Withdrawal of which of the following hormones is the immediate cause of menstruation?
A biology student after studying the different levels of hormones during the menstrual cycle was comparing 2 subjects (Patients). A table was created after looking at the levels of hormones A and B for Subjects 1 and 2. Read the information in the table and answer the question that follows.
| HORMONE A | HORMONE B | |
| Subject 1 | Shows a peak on the 14th Day of the menstrual cycle. | Falls down during the luteal phase. |
| Subject 2 | Shows a peak on the 14th Day of the menstrual cycle. | The level is maintained high in the luteal phase. |
Subject 2 has a higher level of hormone B, which is ______
Distinguish between pollination and fertilisation. Mention the site and product of fertilisation in a flower.
Draw a neat, labelled diagram of a pistil showing pollen tube growth and its entry into the ovule.
Hormones responsible for menstrual cycle are produced from ______.
Exit from the cell cycle and remain dormant for long time by a cell is represented by one of the following phases of the cell cycle:
The Corpus luteum grows during menstruation.
Menstruation is triggered by an abrupt decline in the amount of ______.
The main function of mammalian corpus luteum is to produce ______.
Identify the correct statement from the following:
A human female experiences two major changes, menarche and menopause during her life. Mention the significance of both the events.
Which of the following statement is correct?
Write a short note on Secretory Phase.
