1 In the cytoplasm, the mitotic spindle, consisting of microtubules and other proteins, forms between the two pairs of centrioles as they migrate to opposite poles of the cell. 2  The nuclear envelope disappears at the end of prophase. 3  This signals the beginning of the substage called prometaphase.
  Percussion Family. The Timpani is struck by mallets ... any instrument that requires a percussive touch is a member of this family ...surprisingly enough, and a little â¦ known fact, the Piano is also a member of the Percussion Family ... a key must be struck to produce a tone!!5 people found this useful.he Timpani is struck by mallets ... any instrument that requires a percussive touch is a member of this family ...
Summary. Timpani came in to military use in 15th century Europe and became part of the orchestra by the 17th Century. The orchestra originally had two timpani made of copper with calfskin drum heads. Modern orchestras use four timpani commonly made of fiberglass with plastic drum heads.