When ==Key Stage 3=====Meaning===[[Menstruation]], sometimes called a '''period''', is the stage in the [[Menstrual Cycle|menstrual cycle]] in which the thick lining of the [[Uterus]] breaks down and leaves the body through the [[vagina]]. ==Key Stage 4=====Meaning===[[Menstruation]], sometimes called a '''period''', is the stage in the [[Menstrual Cycle|menstrual cycle]] in which the thick lining of the [[Uterus]] breaks down and leaves the body through the [[vagina]]. ===Extra Information==={{#ev:youtube|https://www.youtube.com/watch?v=ayzN5f3qN8g}}