The Pre-Tribulation Rapture

We examine the doctrine that the Rapture occurs before the Tribulation begins. Did Jesus and the Apostles teach a separate Rapture apart from the Second Coming? Is there a Rapture without Resurrection? Is the Rapture tied to the Last Trumpet? Since there are uncountable numbers saved according to Rev. 7:14, how could that happen if the Holy Spirit has been removed during the Great Tribulation?