Joints are where two bones meet they form a joint.It may be a fixed joint as in the junction of the hip girdle and the vertebral column or a moveable joint as in the knee.Two important types of moveable joint are the ball and socket joints of the hip and the shoulder and the hinge joints of the elbow and knee.The balla ns socket allows movement forwards,backwards and sideways,while a hinge joint allows movement in only one direction.Where the surfaces of the bones in a jointrub over each other,they are covered with smooth cartilage wich reduces the friction between them.Friction is also reduced by a thin layer of a fluid called synovial fluid. Muscle:there are three main types of muscle.Skeletal muscle(or striated,or voluntary muscle).Smooth muscle(or unstriated,or involuntary muscle).Cardiac muscle is found in the heart. The energy for muscle contraction needs sugar to transform it into glycogen in the muscle fat to react to a stimulus. Long-Term benefits of exersice:the resting heart rate goes down,the muscles used in exercise grow larger,more enzymes are made in the muscle tissue,your ligaments and tendons become stronger,your joints become more flexible,protection from heart attacks and well-being. Structure of the teeth:enamel covers the exposed part,or crown.Dentine:is rather like bone and softer than enamel.It is a living tissue with threads of cytoplasm runing through it.Pulp: in the centre of the tooth is soft connective tissue.It contains cells which make the dentine.There are blood vessels and sensory nerve endings which are sensitive to hat and cold but give only the sensation of pain. Cement:it covers the root of the tooth.