In a young female of reproductive age with regular menstrual cycles of 28 days, if ovulation occurs around 14th day of periods. When is the first polar body extruded?
**Core Concept**
The meiotic division of oocytes in females is a complex process involving the formation of two polar bodies. The first polar body is extruded during the first meiotic division, which occurs before ovulation. This process is essential for the release of a mature oocyte from the ovary.
**Why the Correct Answer is Right**
The first polar body is extruded during the first meiotic division, which occurs just before ovulation. This division is triggered by the LH surge, which causes the oocyte to undergo meiosis I. During this division, the oocyte undergoes a reduction in chromosome number, resulting in a secondary oocyte and a first polar body. The first polar body contains a haploid set of chromosomes, which will eventually degenerate.
**Why Each Wrong Option is Incorrect**
**Option A:** This option does not specify the correct timing of the first polar body extrusion. While it is true that the first polar body is extruded during meiosis, it does not provide the correct timing in relation to ovulation.
**Option B:** This option is incorrect because the first polar body is extruded before ovulation, not after. Ovulation marks the release of the mature oocyte from the ovary, which occurs after the first polar body has been extruded.
**Option C:** This option is incorrect because the first polar body is extruded during the first meiotic division, which occurs before ovulation. The second polar body is extruded during the second meiotic division, which occurs after ovulation.
**Clinical Pearl / High-Yield Fact**
The first polar body is extruded around 24-26 hours before ovulation, making this a critical period for fertilization. Understanding the timing of the first polar body extrusion is essential for clinicians to provide accurate information to patients about their fertility window.
**Correct Answer:** C.