The doctors reveal how important cartilage is to your body with the help of a suit of armour, and they find out what it takes to be a hospital porter in Operation Takeover. Dr Chris meets Nala the dog to see how she helps patients in hospital, and we meet two more of our ouch patients to find out what it's like to be a regular hospital patient. Meanwhile, in accident and emergency, one patient arrives by air ambulance and another is treated for a spring stuck in his thumb.