Summary:
- Skeletal muscles are attached to the skeleton and cause bones to move when they contract.
- A skeletal muscle contains bundles of muscle fibers inside a “coat” of connective tissue.
- To move bones in opposite directions, pairs of muscles must work in opposition.
- In exercises such as running, the cardiac muscle contracts faster and the heart pumps more blood.
- Continued exercise is necessary to maintain bigger, stronger muscles.
- If you don’t use a muscle, it will get smaller and weaker—so use it or lose it.