Hostile World

S1, E4: Michael Mosley reveals the ingenious ways in which our bodies defend themselves against a hostile world. We meet Cristian, a bull jumper whose muscles give him the strength to avoid a violent death, and Johnny who gets injured almost every week to earn his living, relying upon his body's remarkable ability to heal. Mosley also explores how surgeons use medical expertise to exploit the body's natural powers of healing. Richard Edwards is filmed having his damaged hands cut off and replaced with someone else's - the first time something this radical has ever been attempted.