During Implantation, the blastocyst is embedded in which layer of the uterus?

Options

A. Trophoblast
B. Endometrium
C. Myometrium
D. Perimetrium

Answer

To answer the question "During Implantation, the blastocyst is embedded in which layer of the uterus?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Uterus Structure**: The uterus has three main layers - the endometrium (innermost layer), myometrium (middle muscular layer), and perimetrium (outer thin layer).

2. **Identifying the Role of the Endometrium**: The endometrium is the layer that thickens during the menstrual cycle and is crucial for implantation. It is glandular and undergoes cyclic changes influenced by hormones.

3. **Timing of Implantation**: Implantation occurs approximately 7 to 8 days after fertilization, when the blastocyst reaches the uterus.

4. **Blastocyst Structure**: The blastocyst consists of two types of cells: the outer trophoblast cells, which will help in implantation, and the inner cell mass, which will develop into the embryo.

5. **Conclusion**: The blastocyst embeds itself in the endometrium, the innermost layer of the uterus, which is thickened under the influence of progesterone from the corpus luteum.

### Final Answer:
The blastocyst is embedded in the **endometrium** layer of the uterus during implantation.

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