Best Ever Q&A Space Our World Nature History Science & Technology Human Body Senses & Organs Science of Life Chemicals & Matter Atoms & Molecules Materials Forces & Energy Sound Electricity & Magnetism Heat & Light Everyday Science Industry Transportation Computers Machines Ships Undersea Exploration Land Travel Cars Flight Structures Buildings Farming	Human Body How do our joints work? How does the heart work? What are veins and arteries? What is inside a bone? How many bones do we have? How do muscles work? What is the skin for?   Previous: Back to Human Body Book: Best Ever Q&A Section: Science & Technology Chapter: Human Body