Outer Space Exposure...

In scores of science fiction stories, hapless adventurers find themselves unwittingly introduced to the vacuum of space without proper protection. There is often an alarming cacophony of screams and gasps as the increasingly bloated humans writhe and spasm. Their exposed veins and eyeballs soon bulge in what is clearly a disagreeable manner. The ill-fated adventurers rapidly swell like over-inflated balloons, ultimately bursting in a gruesome spray of blood.
As is true with many subjects, this representation in popular culture does not reflect the reality of exposure to outer space. Ever since humanity first began to probe outside of our protective atmosphere, a number of live organisms have been exposed to vacuum, both deliberately and otherwise. By combining these experiences with our knowledge of outer space, scientists have a pretty clear idea of what would happen if an unprotected human slipped into the cold, airless void.