Why do different tissues in the body age at different rates?

Answer: Tissues have different cell turnover

All tissues age the same — Wrong. While some aging processes are shared, tissues like the heart and liver age at different rates due to differences in cell division and repair. For example, skin cells turn over quickly, while neurons rarely divide, leading to distinct aging patterns.

Only the brain ages — Wrong. The brain does age, but it is not the only tissue that ages. Other tissues like the kidneys, muscles, and skin also show clear signs of aging, such as reduced function and increased damage over time.

Tissues have different cell turnover ✓ — Correct! Tissues age at different rates primarily because their cells have different turnover rates. Tissues with high cell turnover, like the gut lining, can renew themselves frequently, while tissues with low turnover, like the heart, accumulate damage over time. This explains why some organs show age-related decline earlier than others.