Pituitary gland is derived from

Options

A. ectoderm
B. endoderm
C. mesoderm
D. None of these

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the embryonic origin of the pituitary gland. We need to identify which of the three germ layers (ectoderm, endoderm, or mesoderm) gives rise to the pituitary gland.

2. **Identifying Germ Layers**: During the process of gastrulation, three primary germ layers are formed: ectoderm, endoderm, and mesoderm. Each of these layers gives rise to different tissues and organs in the body.

3. **Ectoderm**: The ectoderm is the outermost germ layer. It is responsible for forming structures such as the central nervous system, peripheral nervous system, and the pituitary gland. Other derivatives of the ectoderm include sensory organs (like the eyes and ears) and mammary glands.

4. **Endoderm**: The endoderm is the innermost layer and primarily forms the epithelial lining of the gastrointestinal tract and associated organs such as the liver, pancreas, thymus, and thyroid.

5. **Mesoderm**: The mesoderm is the middle layer, which gives rise to structures such as bones, cartilage, muscles, the heart, kidneys, and gonads.

6. **Conclusion**: Since the pituitary gland is derived from the ectoderm, we can conclude that the answer to the question is that the pituitary gland is derived from the ectoderm.

### Final Answer:
The pituitary gland is derived from the ectoderm.

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