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प्रश्न
Explain the role of hormones during the menstrual cycle.
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उत्तर
Role of hormones during the menstrual cycle are:
- The menstrual cycle is regulated by five main hormones: Gonadotropin-releasing hormone (GnRH), Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), estrogens, and progesterone.
- GnRH is secreted by the hypothalamus and stimulates the anterior pituitary gland to release FSH and LH.
- FSH causes the development of ovarian follicles and stimulates them to produce estrogens.
- Estrogens repair and thicken the uterine lining (endometrium) after menstruation and stimulate the pituitary to release LH.
- A peak in estrogen levels causes an LH surge in the middle of the cycle (around day 14), triggering ovulation the release of the mature egg from the follicle.
- After ovulation, LH transforms the ruptured follicle into the corpus luteum, which secretes both progesterone and estrogens.
- Progesterone prepares the endometrium for implantation by making it thick, moist, and vascular; it also inhibits the release of GnRH, thus reducing FSH and LH secretion to prevent development of new follicles.
- If fertilization does not occur, the corpus luteum degenerates, leading to a drop in progesterone and estrogen levels.
- The decrease in hormones causes the endometrial lining to break down and menstruation to begin, marking the start of a new cycle.
- With progesterone level low, inhibition on FSH is removed, so FSH levels rise again to start follicle development for the next cycle.
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संबंधित प्रश्न
Explain the events that occur in a graafian follicle at the time of ovulation and thereafter.
Describe the structure of a Graafian follicle.
State the names of four hormones which control menstrual cycle.
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?
Answer the following type of question Assertion (A) and Reason (R).
(A) - Ovulation is the release of the ovum from the Graafian follicle.
(R) - It occurs during the follicular 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 |
All occur during follicular phase of menstrual cycle, EXCEPT
When does the following step take place?
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 ______
The first menstruation is called ______.
