| A | B |
|---|
| calcium | the mineral in bones that makes them strong |
| skeleton | Our system of bones is called our |
| ribs | Important organs like our heart and lungs are kept safe behind our |
| marrow | Red blood cells are created deep inside our bones in the |
| skull | This protects our brain |
| fiber | A slender, threadlike object |
| bundled | A group of things gathered close together |
| striated | Another word for striped |
| cardiac | A word used to describe things related to the heart |
| Involuntary | Cardiac and smooth muscles are both this type of muscle |
| 2 ways muscles help us | give our bodies shape and help us move |
| 3 kinds of joints | ball & socket, hing, sliding |
| Why are bones hard? | They give us support and protection |
| What does bone marrow do? | It is where red blood cells are made. |
| The third inside layer of bone | Bone Marrow |
| light | The middle layer of our bones is |
| Sliding Joints | help wrists and ankles move in all directions |
| Elbows and knees | examples of hinge joints |
| 29 | How many bones in our skull are joined by cartilage? |
| Hinge Joint | This type of joint is stronger than a ball and socket joint. |
| Cardiac muscles | Involuntary muscles that help pump our blood |
| Tendons | These help protect muscles from strain |
| 3 | How many important body parts come together in voluntary movement? |
| hard ridges that run from our fingers to our wrists | Example of tendons |
| contracts | When a muscle shortens |
