Primary lymphoid organ on the ventral side of heart is

Options

A. spleen
B. thyroid
C. thymus
D. adenoid

Answer

To determine the primary lymphoid organ located on the ventral side of the heart, we can follow these steps:

1. **Understand the Options**: We have four options to consider: spleen, thyroid, thymus, and adenoid. Each of these has different functions and locations in the body.

2. **Identify the Location of Each Organ**:
- **Spleen**: This organ is located in the upper left part of the abdomen and is primarily involved in filtering blood and immune response.
- **Thyroid**: The thyroid gland is located in the neck and is responsible for regulating metabolism through hormone production.
- **Thymus**: The thymus is located in the upper front part of the chest, specifically in the anterior mediastinum, which is behind the sternum and in front of the heart.
- **Adenoid**: Adenoids are located in the nasopharynx and are involved in immune function, but they are not considered a primary lymphoid organ.

3. **Determine the Primary Lymphoid Organ**: The thymus is recognized as a primary lymphoid organ because it is where T-cells mature, which are crucial for the adaptive immune response.

4. **Conclusion**: Based on the location and function of these organs, the primary lymphoid organ on the ventral side of the heart is the thymus.

Thus, the correct answer is **thymus** (option 3).