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

Options

A. Spleen
B. Kidney
C. Thymus
D. Lymph nodes

Answer

To solve the question "Which of the following is not a major organ of the lymphatic system?" we will analyze each option provided and determine which organ does not belong to the lymphatic system.

### Step-by-Step Solution:

1. **Identify the Organs Listed**: The question provides four options: spleen, kidney, thymus, and lymph nodes. We need to evaluate each of these organs to see if they are part of the lymphatic system.

2. **Evaluate the Spleen**:
- The spleen is known for its role in filtering blood and removing old red blood cells (RBCs).
- It is often referred to as the "graveyard of RBCs" because it destroys old and damaged cells through a process called phagocytosis.
- **Conclusion**: The spleen is a major organ of the lymphatic system.

3. **Evaluate the Kidney**:
- The primary function of the kidney is to filter blood and excrete waste products through urine.
- The kidneys are part of the excretory system, not the lymphatic system.
- **Conclusion**: The kidney is NOT a major organ of the lymphatic system.

4. **Evaluate the Thymus**:
- The thymus is located just below the chest and is involved in the development of T lymphocytes (a type of white blood cell).
- It plays a crucial role in the immune response and is part of the lymphatic system.
- **Conclusion**: The thymus is a major organ of the lymphatic system.

5. **Evaluate the Lymph Nodes**:
- Lymph nodes are small structures that filter lymph fluid and are integral to the immune system.
- They contain lymphocytes that help in the body's defense mechanisms.
- **Conclusion**: Lymph nodes are major organs of the lymphatic system.

6. **Final Answer**: Based on the evaluations, the only organ listed that is not a part of the lymphatic system is the **kidney**.