Menstrual flow occurs due to lack of

Options

A. FSH
B. Oxytocin
C. Vasopressin
D. Progesterone

Answer

**Step-by-Step Solution:**

1. **Understanding Menstrual Flow**: Menstrual flow, also known as menstruation or periods, is the process of vaginal bleeding that occurs in females approximately every 28 days as part of the menstrual cycle.

2. **Role of Fertilization**: Menstrual flow occurs when fertilization does not take place. If an ovum (egg) is not fertilized by sperm, the body prepares to shed the uterine lining.

3. **Identifying Hormones**: The question asks about the lack of a specific hormone that leads to menstrual flow. The options provided include FSH, oxytocin, vasopressin, and progesterone.

4. **Evaluating FSH (Follicle Stimulating Hormone)**: FSH is important for the development of ovarian follicles during the follicular phase of the menstrual cycle. However, it does not directly cause menstrual bleeding. Thus, FSH is not the correct answer.

5. **Evaluating Oxytocin**: Oxytocin is involved in uterine contractions during childbirth, not in the menstrual cycle. Therefore, it is also not the correct answer.

6. **Evaluating Vasopressin**: Vasopressin, also known as antidiuretic hormone (ADH), regulates water retention in the kidneys and does not play a role in the menstrual cycle. Hence, it is not the correct answer.

7. **Evaluating Progesterone**: Progesterone is produced by the corpus luteum after ovulation and is crucial for maintaining the thick endometrial lining of the uterus. If fertilization does not occur, the corpus luteum degenerates, leading to a decrease in progesterone levels. This decrease causes the shedding of the endometrial lining, resulting in menstrual flow.

8. **Conclusion**: The correct answer is that menstrual flow occurs due to the lack of progesterone.

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