Human Body

Introduction and Historical Background

What is the average life span of cells in the human body?

The human body is self-repairing and self-replenishing. According to one estimate, almost 200 billion cells die each hour. In a healthy body, dying cells are simultaneously replaced by new cells.

Cell Type Length of Time
Red blood cells 120 days
Lymphocytes Over 1 year
Other white blood cells 10 hours
Platelets 10 days
Bone cells 25–30 years
Brain cells* Lifetime
Colon cells 3–4 days
Liver cells 500 days
Skin cells 19–34 days
Spermatozoa 2–3 days
Stomach cells 2 days

*Brain cells are the only cells that do not divide further during a person’s lifetime. They either last the entire lifetime or, if a cell in the nervous system dies, it is not replaced.


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