Medulla oblongata develops from

Options

A. Ectoderm
B. Endoderm
C. Mesoderm
D. Mesenchyme.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the embryonic origin of the medulla oblongata, which is a part of the brain.

2. **Identifying the Germ Layers**: In embryology, there are three primary germ layers: ectoderm, mesoderm, and endoderm. Each layer gives rise to different structures in the body.
- **Ectoderm**: Forms the nervous system and skin.
- **Mesoderm**: Forms muscles, bones, and connective tissues.
- **Endoderm**: Forms the gastrointestinal tract and associated organs.

3. **Focusing on the Medulla Oblongata**: The medulla oblongata is a part of the central nervous system, which is derived from the ectoderm.

4. **Eliminating Incorrect Options**:
- **Endoderm**: This layer does not contribute to the nervous system; it forms the digestive tract.
- **Mesoderm**: This layer is responsible for forming muscles and connective tissues, not the nervous system.
- **Mesenchyme**: This is not a primary germ layer but rather a type of connective tissue derived from mesoderm.

5. **Conclusion**: Since the medulla oblongata is derived from the ectoderm, the correct answer is option A.

**Final Answer**: The medulla oblongata develops from **ectoderm** (Option A).

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