Mature red blood cells do not contain a nucleus, so they are not able to repair the normal wear and tear they experience traveling throughout the body. As a result, they become fragile and damaged after three or four months. The outer membranes of damaged cells may actually rupture as the cells pass through narrow sections in the circulation system. These damaged cells are removed from circulation by the spleen, and most of the leftover compounds, such as iron, are recycled to form new red blood cells. It is perfectly normal for red blood cells to become damaged over time: old cells die in our bodies every day and new cells are created every day.

Red blood cells get damaged very often-- in fact, they are cells that are not designed for a long life.Red blood cells are primarily manufactured by cells in bone marrow, and then released into the bloodstream to perform the important job of ferrying oxygen from our lungs throughout our body. Most red blood cells break down and are disposed of the body within a few weeks of being produced.

However, genetic diseases can cause red blood cells to be made incorrectly, so that there is a specific type of damage to all the red blood cells. The best example of this is sickle cell anemia, a genetic disease that causes red blood cells to be malformed (a crescent or sickle shape instead of a normal circular shape) because of a malfunctioning hemoglobin protein. This causes the body to not ferry oxygen as well, resulting in fatigue, tissue damage, and other problems.

If the damage involved the red blood cell (RBC) being broken open, then your body's immune system would remove the broken cell and get rid of all of the leaked out parts as part of the immune surveillance system. If the cell was damaged by a toxic chemical - maybe causing it to be unable to create new energy or carry oxygen- it might undergo a process called "apoptosis" or a type of programmed cell death. Regardless, your body is able to keep a pretty constant level of RBCs present in your blood - there is a feedback mechanism, a sort of "detector" that tells your bone marrow when new RBCs are needed. So if some are damaged or die, your bone marrow starts making more right away. The source of these new cells are bone marrow STEM CELLS, which I am sure you have heard about in the news. These stem cells have the remarkable ability to keep producing all of the cells of your blood and immune system throughout your entire life!

Red blood cells don't have a nucleus, so they don't have the ability to repair themselves. The kidneys filter out dead red blood cells from the blood. Some of the materials get recycled, but others are excreted with the urine. This is why people who get heavy metal poisoning (like arsenic or lead) sometimes get dark colored or funny-smelling urine: the body is trying to clean out all the red blood cells destroyed by the heavy metals. (There are other causes of dark urine, too.)

This is a good question, because red blood cells actually get damaged all the time. In fact, they are designed to wear out and be replaced on a regular basis. Red blood cells are a unique sort of cell - they don't have a nucleus. Since the nucleus contains the DNA blueprints that cells need to make new proteins, a red blood cell cannot make new proteins and cannot repair itself.

As red blood cells get old, they are destroyed by cells in the spleen and lymph nodes. This happens whether the red blood cell is damaged or not. Red blood cells usually live about 3 months before being destroyed in this way.

If a red blood cell gets damaged and ruptures in the bloodstream before it can be destroyed by the spleen, your body tries to recycle the contents of the cell. Most importantly it tries to recycle the hemoglobin, which is the most important part of the cell - it is the chemical that allows the cell to carry oxygen around the body. There are proteins called haptoglobins floating in the blood, and when a red blood cell ruptures, the haptoglobin binds to the hemoglobin that is released and carries it to the spleen or lymph nodes where it can be recycled. Other bits and pieces of the ruptured cell will pass out of the blood into the kidney and be excreted in the urine.

Red blood cells rupture at a fairly low rate all the time, but if you contract a disease that causes it to happen more frequently, you may show signs of anemia. Anemia is a condition in which your body does not have enough red blood cells to function properly.

I hope this answers your question.