Lesson 21.3: Vocabulary I Match the vocabulary word with the proper definition.

Definitions

H 1. muscle tissue that is attached to bone

2. long, thin muscle cell that has the ability to contract, or shorten

3. theory that explains muscle contraction by the sliding of myosin filaments over actin filaments within muscle fibers

4. tough connective tissue that attaches skeletal muscle to bones of the skeleton

5. human body system that includes all the muscles of the body

6. organs composed mainly of muscle cells

7. the region between two Z lines

8. involuntary, nonstriated muscle that is found in the walls of internal organs such as the stomach

9. organelles contained within each muscle fiber

10. involuntary, striated muscle found only in the walls of the heart

11. tiny structures within the myosin filaments, that can attach to actin filaments

Terms

a. cardiac muscle

b. cross bridges

c. muscle fiber

d. muscles

e. muscular system

f. myofibril

g. sarcomere

h. skeletal muscle

i. sliding filament theory

j. smooth muscle