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प्रश्न
Describe the roles of pituitary and ovarian hormones during the menstrual cycle in a human female.
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उत्तर
- Pyramid of energy is a graphical representation of the amount of accumulated energy per unit area in different trophic levels of a food chain.
- An energy pyramid is always upright because there is a gradual decrease in energy at successive trophic levels. This happens because, according to the 10% law of energy transfer, only 10% of the total energy is transferred from one trophic level to another.
- The energy is highest at the producer level and it gradually decreases on moving from herbivores to carnivores.
- As the oestrogen levels increase the endometrium begins to regenerate along with the development of uterine glands and network of blood vessels.
- The corpus luteum starts secreting progesterone, oestrogen, and inhibin. The endometrium proliferates under the influence of these hormones, as do the endometrial gland and blood vessels. Inhibin inhibits FSH and GnRH secretion.
- When there is no fertilisation, the corpus luteum degenerates, progesterone levels drop, and the next menstrual cycle begins.
- Thus, pituitary and ovarian hormones work together to regulate all phases of the menstrual cycle.
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संबंधित प्रश्न
Draw a graafian follicle and label antrum and secondary oocyte.
What are the phases of the menstrual cycle? Indicate the changes in the ovary and uterus.
Explain the various phases 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 |
Mainly which type of hormones control the menstrual cycle in human beings?
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. |
If the peak of Hormone A does not appear in the study for Subject 1, which of the following statement is true?
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.
Menstruation is triggered by an abrupt decline in the amount of ______.
The menstrual cycle begins with ______
Write a short note on Secretory Phase.
