Which of following is not a major organ of lymphatic system?

Options

A. Spleen
B. Kidney
C. Thoracic duct
D. Jugular vein

Answer

To determine which of the following is not a major organ of the lymphatic system, we need to analyze the options provided. The lymphatic system plays a crucial role in the immune system and is responsible for transporting lymph, a fluid that contains white blood cells, throughout the body. Let's evaluate the options one by one.

1. **Spleen**: The spleen is indeed a major organ of the lymphatic system. It is responsible for filtering blood, recycling iron, and storing white blood cells. It plays a significant role in the immune response.

2. **Thymus**: The thymus is another major organ of the lymphatic system. It is where T-cells mature, which are essential for adaptive immunity.

3. **Thoracic Duct**: The thoracic duct is the largest lymphatic vessel in the body. It collects lymph from various regions and drains it into the bloodstream. Therefore, it is also a significant part of the lymphatic system.

4. **Jugular Vein**: The jugular vein is a major vein that carries blood from the head back to the heart. Although it is associated with the lymphatic system through the jugular trunk, it is primarily a blood vessel and not a lymphatic organ.

5. **Kidney**: The kidney is primarily an organ of the excretory system responsible for filtering blood and producing urine. It does not play a role in the lymphatic system.

Based on this analysis, the correct answer is **Kidney**, as it is not a major organ of the lymphatic system.

### Step-by-Step Solution:
1. **Understand the Lymphatic System**: Recognize that the lymphatic system is part of the immune system and is responsible for transporting lymph.

2. **Evaluate Each Option**:
- **Spleen**: Major organ of the lymphatic system.
- **Thymus**: Major organ of the lymphatic system.
- **Thoracic Duct**: Major lymphatic vessel.
- **Jugular Vein**: Primarily a blood vessel, not a lymphatic organ.
- **Kidney**: Not part of the lymphatic system.

3. **Identify the Correct Answer**: Conclude that the kidney is not a major organ of the lymphatic system.