Fetal ejection reflex in human females is induced by

Options

A. Release of oxytocin from pituitary
B. Fully developed fetus and placenta
C. Differentiation of mammary glands
D. Pressure exerted by amniotic fluid

Answer

To solve the question regarding what induces the fetal ejection reflex in human females, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Fetal Ejection Reflex**:
- The fetal ejection reflex is a physiological response that occurs during parturition (the process of giving birth). It involves the expulsion of the fetus from the uterus.

2. **Identify the Mechanism of Parturition**:
- Parturition is described as an induced complex neuroendocrine mechanism. This means that it involves both nerve signals and hormonal changes.

3. **Determine the Source of Signals**:
- During parturition, signals originate from the fully developed fetus and the placenta. These signals are crucial for initiating the process of labor.

4. **Effects of the Signals**:
- The signals from the fetus and placenta lead to mild uterine contractions. As these contractions become stronger, they contribute to the expulsion of the fetus from the uterus.

5. **Evaluate the Options**:
- **Option A**: Release of oxytocin from the pituitary - While oxytocin plays a role in labor, it is not the primary inducer of the fetal ejection reflex.
- **Option B**: Fully developed fetus and placenta - This option correctly identifies the source of the signals that induce the fetal ejection reflex.
- **Option C**: Differentiation of mammary glands - This is related to lactation, not the ejection reflex.
- **Option D**: Pressure exerted by amniotic fluid - While this may contribute to the process, it is not the primary inducer.

6. **Conclusion**:
- Based on the understanding of the mechanisms involved in parturition, the correct answer is **Option B: Fully developed fetus and placenta**.

### Final Answer:
The fetal ejection reflex in human females is induced by **fully developed fetus and placenta** (Option B).