Which one of the following organs of the human body breaks down the old red blood cells and stores iron from them ?

The spleen is the primary organ responsible for the breakdown of old or damaged red blood cells (RBCs) and the subsequent recycling of iron. Specialized macrophages, specifically splenic red pulp macrophages, identify and phagocytose senescent erythrocytes that have lost their deformability [t1][t2]. During this process, known as erythrophagocytosis, the hemoglobin from the RBCs is broken down, and the iron is either stored within the spleen as ferritin or hemosiderin or returned to the circulation to support new hemoglobin synthesis [t1][t3]. While the liver's Kupffer cells also participate in this reticuloendothelial function, the spleen's unique architecture and fluid dynamics make it the critical site for filtering and processing aged RBCs [t4][t5]. In contrast, the kidneys focus on waste excretion [c3], the pancreas on digestion and glucose regulation [c2], and the gall bladder on bile storage.

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC8615895/
2. [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC8469827/
3. [3] https://www.nature.com/articles/s42003-024-05802-9
4. [4] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > Small Intestine > p. 126
5. [5] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > What you have learnt > p. 99