Biology · Human Reproduction · NEET
LH does it. Both LH and FSH reach a peak at mid-cycle, but NCERT clearly says the rapid rise of LH to its maximum (the LH surge) is what ruptures the Graafian follicle and releases the ovum. FSH mainly helps follicles grow. So for NEET, the direct cause of ovulation is the LH surge.
Both ideas are correct and linked. The growing follicles secrete high estrogen at mid-cycle. This high estrogen triggers the LH surge, and the LH surge then causes ovulation. In the 2020 options, LH and FSH were given as 'low' (wrong) and estrogen as 'high' (right), so 'high estrogen' was the only correct choice. Learn the chain: high estrogen -> LH surge -> ovulation.
A secondary oocyte is released, and NCERT also calls it the ovum. The secondary oocyte is still arrested in meiosis II. It only finishes meiosis II later, at the moment a sperm fuses with it. So 'ovum released at ovulation' and 'secondary oocyte released' mean the same released cell.
Ovulation, not menstruation. NEET 2025 gave a trap statement saying 'LH surge leads to disintegration of the endometrium and onset of menstrual bleeding' — this is FALSE. The LH surge causes ovulation. Menstrual bleeding happens later, when the corpus luteum breaks down and progesterone falls.
Around day 14, the middle of the cycle. NCERT says both LH and FSH peak in the middle of the cycle (about the 14th day), and the LH surge at this point causes ovulation. This is why the follicular phase ends and the luteal phase begins near day 14.
The zona pellucida. The secondary oocyte forms a new membrane called the zona pellucida before ovulation, and it is surrounded by the corona radiata (granulosa cells). NEET 2026 directly asked this: the covering of the ovum at ovulation is the zona pellucida.
Which of the following hormone levels will cause release of ovum (ovulation) from the Graafian follicle?
Statement I: The primary follicles get surrounded by more layers of granulosa cells, a theca and shows fluid filled cavity antrum. Now it is called secondary follicle. Statement II: Graafian follicle ruptures to release the secondary oocyte from the ovary by the process called ovulation. Choose the correct answer.
Statement I: Ovulation is caused by LH surge leading to rupture of Graafian follicles. Statement II: The Graafian follicle remaining after ovulation transforms into the corpus luteum and secretes a large amount of estrogen. Choose the most appropriate answer.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Ovulation is the rupture of the mature Graafian follicle to release the secondary oocyte (ovum) from the ovary, caused by the mid-cycle LH surge.
The LH surge is the rapid rise of luteinizing hormone to its maximum level in the middle of the menstrual cycle (about day 14), which triggers ovulation.
Around the 14th day of a 28-day cycle, at the middle of the cycle, when LH and FSH reach their peak.
No. FSH mainly stimulates follicular growth. The LH surge is the hormone event that actually ruptures the follicle and causes ovulation.
The luteal phase begins. The leftover Graafian follicle becomes the corpus luteum, which secretes progesterone to maintain the endometrium for a possible pregnancy.
The secondary oocyte, also called the ovum. It is arrested in meiosis II and finishes meiosis II only if a sperm fuses with it.
