Do You Really Have a New Body Every 7 Years?

The video debunks the myth that the human body replaces all its cells every seven years. It explains that while many cells do regenerate, the rate varies significantly across different cell types. Some cells, like those in the stomach, are replaced frequently, while others, like heart muscle cells, regenerate very slowly. Certain cells, such as neurons in the cerebral cortex, are never replaced. The video also discusses how carbon-14 from nuclear testing has helped scientists determine the age of cells by measuring its concentration in DNA, which remains constant throughout a cell's life.

Which types of cells in the human body are never replaced?

What is the significance of nuclear testing in understanding cell replacement?