| A | B |
|---|
| tissue | cells of same type working together |
| organs | tissues of different types |
| cardiac muscle | heart |
| smooth muscle | organ muscle |
| striated muscle | skeletal muscle |
| lungs | organ in respiratory system |
| capillaries | tiny blood vessels |
| heart | main organ in circulatory system |
| arteries | carries blood away from heart |
| veins | returns blood to the heart |
| brain | control center of nervous system |
| neurons | nerve cells |
| nerve | group of neurons |
| spinal cord | tube of nerves in backbone |
| esophagus | tube connecting mouth to stomach |
| stomach | bag of smooth muscles |
| small intestine | most digestion done here |
| large intestine | remove water from digested food |
