Post-mitotic cells are cells that have permanently exited the cell cycle and are no longer capable of dividing. This means they have lost the ability to undergo mitosis, the process of cell division that produces two identical daughter cells.

Here are some examples of post-mitotic cells:

* Neurons: These cells in the nervous system are responsible for transmitting information throughout the body. Once they reach maturity, they generally don't divide.

* Cardiac muscle cells: These cells make up the heart muscle and are also post-mitotic. This is why heart attacks can be so devastating, as damaged heart muscle cells cannot be replaced by new ones.

* Skeletal muscle cells: While some muscle stem cells can divide, the majority of skeletal muscle cells are post-mitotic.

* Red blood cells: Mature red blood cells lose their nucleus and other organelles, making them incapable of dividing.

It's important to note that the term "post-mitotic" doesn't necessarily mean the cells are dead. They are still alive and performing their functions, but they simply can't reproduce themselves.