b'ChapterWhere two bones join or articulate, they form a joint.Some joints are fused, so that no motion ispossible (cranial bones).Other joints (synovial joints) allowfor motion and they are held together by tough bands of fibrous tissue called ligaments (knee, elbow, hip). The bones in the arms and legs work like a complex system of levers and pulleys so the hands and feet can position themselves and work.The bones in the fingers and wrist allowyou to grasp objects and write.Bones also store minerals and assist in theproduction of blood cells.Tendons and Muscles are made of special tough cords of fibrous tissue that can lengthen and shorten enabling you to move.Tendons attach muscle to bone. The muscles band together to form muscle groups which work together to enable movement. Muscles are everywhere in your body and form part of your flesh. They allow you to participate in everyday activities like playing sport, to digest food, to walk, jump, run and even smile.When I Am Cold, Why Do I Shiver?When you are cold, your muscles automatically spring to the rescue by quickly contracting and relaxing, causing you to shiver. The contracting and relaxing action creates heat, thereby keeping you warm.20 How Your Body Works20 How Your Body Works'