Adrenal medulla and membranoous labyrinth develop from

Options

A. Ectoderm
B. Endoderm
C. Mesoderm
D. Both B andC

Answer

To determine the developmental origins of the adrenal medulla and membranous labyrinth, we need to analyze the three primary germ layers: ectoderm, endoderm, and mesoderm.

### Step-by-Step Solution:

1. **Identify the Germ Layers**:
- The three primary germ layers in embryonic development are ectoderm, mesoderm, and endoderm. Each layer gives rise to different structures in the body.

2. **Define Each Germ Layer**:
- **Ectoderm**: This is the outermost layer and develops into structures such as the epidermis, nervous system (including the brain and spinal cord), and sensory organs.
- **Mesoderm**: This middle layer forms structures such as muscles, bones, and the circulatory system.
- **Endoderm**: This is the innermost layer and develops into the lining of the digestive tract and associated organs.

3. **Focus on the Adrenal Medulla**:
- The adrenal medulla is part of the adrenal glands and is involved in the production of hormones like adrenaline. It is derived from the ectoderm, specifically from the neural crest cells.

4. **Focus on the Membranous Labyrinth**:
- The membranous labyrinth is a part of the inner ear, which is responsible for hearing and balance. It also develops from the ectoderm.

5. **Conclusion**:
- Both the adrenal medulla and the membranous labyrinth develop from the ectoderm. Therefore, the correct answer to the question is **ectoderm**.

### Final Answer:
Adrenal medulla and membranous labyrinth develop from **ectoderm**.

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