Lesson 21.3: Vocabulary II Name Class Date
Fill in the blank with the appropriate term.
1. Both skeletal and muscles appear striated.
2. Muscle tissue that is attached to is skeletal muscle.
3. Contractions of skeletal muscle are voluntary, or under control
4. Cardiac muscle contains a great many mitochondria, which produce
for energy.
5. Skeletal muscles need a rich blood supply to provide them with
and oxygen and to carry away their wastes.
6. Many skeletal muscles are attached to the ends of bones that meet at a
.
7. Muscles can only contract and cannot actively .
8. To move bones in opposite directions, pairs of must work in
opposition.
9. In exercises such as weight lifting, skeletal muscle contracts against a
force.
10. If you don’t use a muscle, it will get smaller and weaker—so use it or
it.
11. Muscle contraction occurs when muscle fibers get .
12. Within a sarcomere, myosin filaments the actin filaments.