Ectodermal in origin is

Options

A. Pituitary gland
B. pineal body
C. Lens of eye
D. All of the above

Answer

To determine which structures are ectodermal in origin, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Germ Layers**:
- In triploblastic animals, there are three primary germ layers: ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer and gives rise to various structures in the body.

2. **Analyzing the Pituitary Gland**:
- The pituitary gland is responsible for producing several important hormones, including LH (Luteinizing Hormone), FSH (Follicle-Stimulating Hormone), TSH (Thyroid-Stimulating Hormone), and ACTH (Adrenocorticotropic Hormone).
- The pituitary gland originates from the ectoderm, specifically from a structure called Rathke's pouch.

3. **Analyzing the Pineal Body**:
- The pineal gland produces melatonin, which regulates sleep-wake cycles and other circadian rhythms.
- The pineal body is also derived from the ectoderm, specifically from the epithalamus region of the brain.

4. **Analyzing the Lens of the Eye**:
- The lens of the eye is crucial for focusing light onto the retina.
- It originates from the ectoderm, specifically from the surface ectoderm during embryonic development.

5. **Conclusion**:
- Since all three options (pituitary gland, pineal body, and lens of eye) are derived from the ectoderm, the correct answer is "all of the above."

### Final Answer:
**All of the above (Pituitary gland, Pineal body, Lens of eye) are ectodermal in origin.**

---