Overview: The doctors reveal the amazing job your pancreas does to keep your blood sugar levels in check, and they find out what it's like to be the hospital postman in Operation Takeover. Dr Xand investigates how scientists make bioglass to help doctors mend damaged bones, and we catch up with all four of our Ouch patients for one last time. Meanwhile, in accident and emergency, one patient arrives by air ambulance after falling on a spiky fence and another has come off her bike, cutting her chin.