There are many scriptures where death is spoken of as sleep. The disciples thought Jesus was speaking of Lazarus simply resting. 

Jesus clarifies their misunderstanding by using the word "death," but that was not His first choice. This is because God's perspective is different than ours. Death is final to natural man but not to God. There will be a resurrection.

In 2 Corinthians Paul uses natural illustrations to explain the resurrection. He speaks of seeds that are buried in the ground and "die." Then they are resurrected as a plant. 

The plant and the seed bear no resemblance but they are actually the same. The plant is just in a resurrected state. Our physical bodies will die but they will be resurrected just as seeds produce plants.

In the same way that a seed is different than the plant that it produces, our resurrected bodies will be different. Our glorified bodies will be very similar to our physical bodies in appearance. 

This can be said because of what the bible reveals about Jesus' glorified body. He still looked human, He ate food, had the print of the nails in His hands and feet, and He said He had flesh and bones. 

He could appear and disappear. Our resurrected bodies will be immortal (not subject to death). Our resurrected bodies will be like Jesus' resurrected body.

Our present physical bodies are a miraculous creation, our glorified resurrected bodies will have their own glory. 

If this physical body is wonderful, our resurrected body will be even better.