portion of endometrium lying between chorionic villi and myometrium is

Options

A. Decidua basalis
B. Decidua capsularis
C. Decidua vera
D. Decidua parietalis

Answer

To determine the portion of the endometrium that lies between the chorionic villi and the myometrium, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structures Involved**:
- **Chorionic Villi**: These are finger-like projections that extend from the chorion (the outer fetal membrane) into the endometrium. They are crucial for nutrient and gas exchange between the mother and the developing embryo.
- **Myometrium**: This is the muscular layer of the uterus that surrounds the endometrium and provides structural support.

2. **Identify the Layers of the Endometrium**:
- The endometrium consists of several layers, including:
- **Decidua Basalis**: The portion of the endometrium that is in contact with the chorionic villi.
- **Decidua Capsularis**: This layer envelops the embryo and provides protection.
- **Decidua Vera (or Decidua Parietalis)**: This is the remaining part of the endometrium that lines the uterus.

3. **Determine the Relevant Layer**:
- The question specifically asks for the layer that lies between the chorionic villi and the myometrium. The **Decidua Basalis** is the layer that directly interfaces with the chorionic villi and provides nutrition to the embryo.

4. **Conclusion**:
- The portion of the endometrium lying between the chorionic villi and the myometrium is the **Decidua Basalis**.

### Final Answer:
The correct answer is **Decidua Basalis**.

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