Extra embryonic membrane of the mammals embryo are derived from

Options

A. trophoblast
B. follicle cells
C. endodermal cells
D. inner cell mass

Answer

**Step-by-Step Solution:**

1. **Understanding Extra Embryonic Membranes**:
- Extra embryonic membranes are structures that develop outside the embryo and play crucial roles in protection and nourishment during the early stages of development.

2. **Identifying Types of Extra Embryonic Membranes**:
- There are four main types of extra embryonic membranes in mammals:
- Amnion
- Chorion
- Allantois
- Yolk sac

3. **Determining the Origin of Extra Embryonic Membranes**:
- These membranes are derived from the blastocyst (or blastula) stage of embryonic development.

4. **Analyzing the Components of the Blastocyst**:
- The blastocyst consists of two main layers:
- Trophoblast: The outer layer that contributes to the formation of the placenta and extra embryonic membranes.
- Inner Cell Mass: This part develops into the embryo itself.

5. **Selecting the Correct Answer**:
- Since the extra embryonic membranes are derived from the trophoblast of the blastocyst, the correct answer to the question is:
- **Trophoblast**.

6. **Eliminating Incorrect Options**:
- Follicle cells: These are related to the ovarian structure and not involved in the formation of extra embryonic membranes.
- Endodermal cells: These are part of the embryonic layers but do not contribute to the extra embryonic membranes.
- Inner Cell Mass: While it forms the embryo, it does not give rise to the extra embryonic membranes.

**Final Answer**: The extra embryonic membranes of mammal embryos are derived from the **trophoblast**.

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