Question

Why does the lack of pressure in outer space affect what's inside our bodies?

Answer 1

Human bodies are constantly dealing with air pressure, the pressure in our internal organs are that of the pressure on the outside of our body. Our bodies can be flexible enough to cope with different internal and external pressures however if there is a lack of air pressure externally, (non-existent in space)  that, our body cannot handle (like that in space) it would rupture our organs. I don't know enough to go into further depth, apologies.