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Why are menstrual cycles absent during pregnancy? - Biology

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प्रश्न

Why are menstrual cycles absent during pregnancy?

Menstrual cycles are absent during pregnancy. Why?

अति संक्षिप्त उत्तर
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उत्तर

The high levels of progesterone and estrogens during pregnancy suppress the gonadotropins which is required for the development of new follicles. Therefore, a new cycle cannot be initiated.

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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 3: Human Reproduction - VERY SHORT ANSWER [पृष्ठ २१]

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एनसीईआरटी एक्झांप्लर Biology [English] Class 12
पाठ 3 Human Reproduction
VERY SHORT ANSWER | Q 4. | पृष्ठ २१
नूतन Biology [English] Class 12 ISC
पाठ 3 Human Reproduction
TEST YOUR PROGRESS | Q 93. | पृष्ठ ११४

संबंधित प्रश्‍न

Name and explain the role of the inner and middle walls of the human uterus.


How can the scientific understanding of the menstrual cycle of human females help as a contraceptive measure?


Differentiate between the following pair: 

Menarche and menopause 


Explain the changes that occur in the ovary and uterus during menstrual cycle in human females. Mention the influence of pituitary and ovarian hormones in bringing these changes.


Briefly describe the secretory phase of the menstrual cycle.


Give Reasons

Missing of menses is the first indication of pregnancy.


Name the Following

Sloughing of the uterine wall during menstrual flow.


Meanrch, menstrual cycle, and menopause are controlled by ______.


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?


Detection of which hormone in urine is an indicator of pregnancy?


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

Calculate the number of spermatozoa produced by a single primary spermatocyte.


Luteal phase is also known as ____________.


Which set is similar?


Withdrawal of which of the following hormones is the immediate cause of menstruation?


Proliferative phase of menstrual cycle, is also called ______.


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.

The peak observed in Subject 1 and 2 is due to ______ 


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 ______


Menstruation is triggered by an abrupt decline in the amount of ______.


What role does pituitary gonadotropins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions.


The figure show a section of human ovary. Select the option which gives the correct identification of either A or B with function/characteristic.


Spermatogenesis is induced by ______.


Complete the table:

Number Type No. of pairs Region
C1C8 Cervical ______ Neck
T1T12 ______ 12 pairs ______
L1L5 Lumbar ______ Lower back
S1S5 ______ 5 pairs ______
CO1 Coccygeal ______ ______

Name the following:

The permanent stoppage of menstruation in human females around the age of 45 years.


Given below is the diagram depicting the menstrual cycle in human beings. Study it carefully and answer the questions that follow.

  1. Which phases are indicated by ‘C’ and ‘D’?
  2. Name the structures labelled ‘F’. What is its role?
  3. Explain the changes in the level of progesterone during phases ‘C’ and ‘D’.
  4. Which hormone present in the urine confirms pregnancy in human beings?
  5. Identify the structure labelled ‘E’. Name the hormone released by it.

Give a reason for the following:

The second half of the menstrual cycle is called the luteal phase as well as the secretory phase.


In the human menstrual cycle, the ovulation occurs around ______.


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