The last part of the oviduct which has a narrow lumen and joins the uterus is

Options

A. infundibulum
B. ampulla
C. Fimbriae
D. isthmus

Answer

To solve the question regarding the last part of the oviduct that has a narrow lumen and joins the uterus, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Oviduct**:
- The oviduct, also known as the fallopian tube, consists of several parts: the infundibulum, ampulla, isthmus, and fimbriae.

2. **Identify the Parts of the Oviduct**:
- **Infundibulum**: This is the funnel-shaped part of the oviduct closest to the ovary. It has finger-like projections called fimbriae that help in capturing the ovum after ovulation.
- **Ampulla**: This is the middle section of the oviduct where fertilization typically occurs. It is wider than the isthmus.
- **Isthmus**: This is the narrowest part of the oviduct and is located closest to the uterus.

3. **Determine the Function and Characteristics of Each Part**:
- The infundibulum is designed to collect the egg, while the ampulla is where fertilization happens. The isthmus, being narrow, serves as the connecting passage to the uterus.

4. **Conclude with the Correct Answer**:
- Since the question specifically asks for the last part of the oviduct that has a narrow lumen and connects to the uterus, the correct answer is the **isthmus**.

### Final Answer:
The last part of the oviduct which has a narrow lumen and joins the uterus is the **isthmus**.

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