karyolysis

karyolysis /ker′ē·ol″isis/ [Gk, karyon + lysis, loosening] , the dissolution of a cell nucleus. It occurs normally, both as a form of necrobiosis and during the generation of new cells through mitosis and meiosis.

Normal cell with visible nucleolus and karyolysis leaving the cell as a mass of partly denatured protein and complete dissolution of the nucleus (Stevens et al, 2009)