Support Systems BY JOSEPH

the skeletal systems and muscular

information by world book studnets

the skull protects the brain. the chest protects the lungs. the chest also the heart. the spine protects the spinal cord. the joint keeps the bones from rubing together. the tendons move the muscles. the muscles get shorter if you move your arm back. also the muscles get longer if you move your arm forword. the spine protects the nerves. the muscle protects the bones. the bones help the body move. the hardest working muscle is the eye. it takes 17 muscles to smile. it takes 42 muscles to frown.