Is quiescent state reversible?

Yes, quiescence is a state of reversible growth arrest. Quiescent cells are no longer active in the cell cycle but are able to re-enter in response to stimulation by mitogens induced by injury or normal cell turnover. Other factors that can enable the cell to re-enter the cell cycle include growth factors, hormones, and nutrients. It is important to note that certain cells such as mature neurons and cardiac cells do not have the ability to re-enter the cell cycle when they have entered the quiescent state. This is due to their differentiation process and they do not need to continually divide. In contrast, stem cells and immune cells may exit and re-enter the cell cycle in response to specific cues or conditions.