Which one of the following human organs is often called the "graveyard" of RBCs?

Options

A. Gall bladder
B. Kidney
C. Spleen
D. Liver

Answer

To solve the question "Which one of the following human organs is often called the 'graveyard' of RBCs?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Term "Graveyard"**: The term "graveyard" in this context refers to the place where dead or aged red blood cells (RBCs) are disposed of.

**Hint**: Think about where in the body cells are broken down and recycled.

2. **Lifespan of RBCs**: Red blood cells have a lifespan of approximately 120 days. After this period, they become old and need to be removed from circulation.

**Hint**: Consider the lifespan of RBCs and what happens to them after they age.

3. **Role of Macrophages**: Aged RBCs attract autoantibodies, which are recognized by macrophages. Macrophages are immune cells that engulf and digest cellular debris, including dead RBCs.

**Hint**: Recall the function of macrophages in the immune system.

4. **Identifying the Organ**: The organs that are primarily involved in the disposal of aged RBCs are the spleen and the liver. However, the spleen is specifically known for this function and is often referred to as the "graveyard" of RBCs.

**Hint**: Think about which organ is known for filtering blood and dealing with old blood cells.

5. **Evaluating the Options**:
- **Gall Bladder**: Involved in digestion, specifically bile storage. Incorrect.
- **Kidney**: Major excretory organ, removes nitrogenous waste, not involved in RBC disposal. Incorrect.
- **Spleen**: Known as the "graveyard" of RBCs due to its role in filtering and removing aged RBCs. Correct.
- **Liver**: Involved in metabolism and detoxification but not primarily in RBC disposal. Incorrect.

6. **Conclusion**: Based on the above analysis, the correct answer is the **spleen**.

### Final Answer:
The organ often called the "graveyard" of RBCs is the **spleen**.