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

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which organ in the human body is referred to as the "graveyard" of red blood cells (RBCs).

2. **Identifying the Options**: The options provided are gallbladder, kidneys, spleen, and liver.

3. **Function of RBCs**: Red blood cells are responsible for transporting oxygen and carbon dioxide throughout the body. They have a lifespan of about 120 days.

4. **Aging of RBCs**: As RBCs age, they lose their flexibility and elasticity, making it difficult for them to pass through narrow blood vessels.

5. **Role of the Spleen**: The spleen has the narrowest capillaries in the body. When old RBCs try to pass through these capillaries, they get trapped and are filtered out of the bloodstream.

6. **Conclusion**: Since the spleen is responsible for filtering out and breaking down old RBCs, it is often referred to as the "graveyard" of RBCs.

7. **Final Answer**: Therefore, the correct answer to the question is the **spleen**.

---