CBSE 2024 · Region 5 · Set 1 · Q29 · 4 marks
In a human female, the reproductive phase starts on the onset of puberty and ceases around middle age of the female. Study the graph given below regarding menstrual cycle and answer the questions that follow :
(a)Name the hormones and their source organ, which are responsible for menstrual cycle at puberty.(b)For successful pregnancy, at what phase of the menstrual cycle an early embryo (upto $\displaystyle 3$ blastomeres) should be Implanted in the Uterus (IUT) of a human female who has opted for Assisted Reproductive Technology (ART) ? Support your answer with a reason.Name the hormone and its source organ responsible for the events occurring during proliferative phase of menstrual cycle. Explain the event.In a normal human female, why does menstruation only occurs if the released ovum is not fertilised ? Explain.
In a human female, the reproductive phase starts on the onset of puberty and ceases around middle age of the female. Study the graph given below regarding menstrual cycle and answer the questions that follow :
(a)
Name the hormones and their source organ, which are responsible for menstrual cycle at puberty.
(b)
For successful pregnancy, at what phase of the menstrual cycle an early embryo (upto $\displaystyle 3$ blastomeres) should be Implanted in the Uterus (IUT) of a human female who has opted for Assisted Reproductive Technology (ART) ? Support your answer with a reason.
Name the hormone and its source organ responsible for the events occurring during proliferative phase of menstrual cycle. Explain the event.
In a normal human female, why does menstruation only occurs if the released ovum is not fertilised ? Explain.
Marking-scheme solution
(a)
Hormone
Source Organ
FSH
Pituitary gland
LH
Pituitary gland
Estrogen
ovary / graafian follicle
Progesterone
ovary / corpus luteum
(b)
Luteal phase or Secretory phase of the menstrual cycle, as endometrium is grown and suitable for implantation of an early embryo or blastocyst.
Estrogen, ovary / graafian (mature) follicles
Endometrium of uterus regenerates through proliferation.
If ovum is not fertilized corpus luteum degenerates, progesterone level falls, disintegration of endometrium (and its blood vessels), leading to menstrual flow.
Human ReproductionMenstrual CycleUnderstandcase_studymedium
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CBSE Class 12 Biology past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.