The function and role of quiescent hepatic stellate cells is unclear. Downregulation of mitochondrial cytochrome C also reflects the low metabolic state of quiescent stem cells. Activated T lymphocytes have many times higher demand for energy than quiescent ones. As germ cells are quiescent and therefore not dividing, they are not susceptible to mutation. Adult'-type Leydig cells differentiate in the post-natal testis and are quiescent until puberty. In normal liver, stellate cells are described as being in a "quiescent" state. In contrast, E2F repressors stay constant, especially since they are often expressed in quiescent cells. CD34 and Myf5 markers specifically define the majority of quiescent satellite cells. Satellite cells are described as quiescent myoblasts and neighbor muscle fiber sarcolemma. The word "post-mitotic" is sometimes used to refer to both quiescent and senescent cells. Burst synchronization refers to the alignment of bursting and quiescent periods in interconnected neurons. This process is able to bring the hepatocytes back into their quiescent state. Consequently, many genes were repressed, and many quiescent genes were expressed. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. They are potentially quiescent hot luminous blue variables.