At the end of 120 days what do red blood cells do?

At the end of 120 days, red blood cells (erythrocytes) undergo a process called erythrophagocytosis, where they are recognized as old or damaged and are removed from circulation. Here is a summary of what happens to red blood cells after 120 days:

1.Aging: Red blood cells have a lifespan of approximately 120 days in the human body. As they age, they become less flexible and efficient in oxygen transport due to various factors, such as oxidative stress and wear-and-tear.

2.Recognition and tagging: Old or damaged red blood cells are recognized by macrophages, which are specialized cells of the immune system. Macrophages identify specific molecules or markers on the surface of these red blood cells, marking them for destruction.

3.Erythrophagocytosis: Macrophages engulf and internalize the tagged red blood cells through a process called erythrophagocytosis. This process occurs mainly in the spleen, liver, and bone marrow, where macrophages reside.

4.Hemoglobin breakdown: Inside macrophages, the hemoglobin within the red blood cells is broken down into its components: heme and globin. Heme contains iron, which is recycled and reused for the production of new red blood cells.

5.Iron recycling: The iron salvaged from heme is transported to the bone marrow, where it is utilized in the synthesis of hemoglobin for the production of new red blood cells.

6.Bilirubin production: The globin component of hemoglobin is broken down into amino acids, which are further metabolized. One of the breakdown products is bilirubin, a yellow pigment that contributes to the color of bile and urine.

7.Red blood cell destruction products: The remnants of destroyed red blood cells, including bilirubin and other breakdown products, are transported to the liver for further processing and excretion.

By removing old or damaged red blood cells, erythrophagocytosis ensures the efficient functioning of the circulatory system and the continuous delivery of oxygen to tissues and organs.