What really exacly happened during metaphase and anaphase of M phase in interphase of the cell cycle?

We all know that during either mitosis (the production of 2daughter cells with the same diploid state of the parent cell) or meiosis ( the production of daubghter cells with half the chromosomalnuber that of the parent cell) of the cell cycle, the chromosomes before anaphase lined up themselves at the equitorial plane of the cell. At this point what is really going on inbetween centromeres before proanaphase?