Which one of the following statements is incorrect about menstrual cycle ?

Options

A. The first menstruation begins at puberty and is called menarche
B. Lack of menstruation may also occur due to some environmental factors like stress , poor heath
C. Corpus luteum secretes large amounts of progesterone which is essential for maintenance of endometrium
D. In absence of fertillisation ,corpus luteum degenerates in luteal phase and new follicles start developing Immediately ?

Answer

**Step-by-Step Solution:**

1. **Understanding the Menstrual Cycle**: The menstrual cycle involves a series of physiological changes in the female reproductive system, primarily affecting the endometrial lining of the uterus. It typically lasts about 28 days and consists of several phases: the menstrual phase, follicular phase, ovulation, and luteal phase.

2. **Identifying the Statements**: We need to analyze each statement provided in the question to determine which one is incorrect regarding the menstrual cycle.

3. **Evaluating Statement 1**: The first statement claims that the first menstruation begins at puberty and is called Menarche. This is correct; Menarche typically occurs between the ages of 11 and 13.

4. **Evaluating Statement 2**: The second statement discusses the lack of menstruation, stating that various factors, including stress and poor health, can affect menstruation. This is also correct, as menstruation can be influenced by several external and internal factors.

5. **Evaluating Statement 3**: The third statement mentions that the corpus luteum secretes large amounts of progesterone, which is essential for maintaining the endometrium. This is accurate; progesterone is crucial for preparing the endometrium for potential implantation.

6. **Evaluating Statement 4**: The fourth statement claims that in the absence of fertilization, the corpus luteum degenerates, and new follicles start developing immediately. This is incorrect. While the corpus luteum does degenerate in the absence of fertilization, the development of new follicles does not start immediately. Instead, it begins after a few days following the degeneration of the corpus luteum.

7. **Conclusion**: Based on the evaluations, the incorrect statement about the menstrual cycle is the fourth one.

**Final Answer**: The incorrect statement about the menstrual cycle is: "In the absence of fertilization, corpus luteum degenerates and new follicles start developing immediately."

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