The Muscular System
Number the following statements in their proper sequence to describe the contraction mechanism in a
skeletal muscle cell.
____ 1. The action potential triggers the release of calcium, which attaches to myofilaments.
____ 2. The nerve impulse moves through the nerve cell to the axon.
____ 3. Acetylcholine diffuses across the synaptic cleft.
____ 4. Acetylcholine is released.
____ 5. The sacrolemma temporarily allows sodium ions into the cell.
____ 6. The muscle cell shortens and a contraction takes place.
____ 7. The muscle cell becomes positively charged changing the condition of the sacrolemma.
____ 8. An action potential is created.
____ 9. Acetylcholine attaches to receptors on the sacrolemma.
Origin antagonist contractibility isotonic
Insertion lactic acid excitability isometric
Body synergist extensibility atrophy
Prime mover action potentials elasticity hypertrophy
1. ______________________ muscle shortens or contracts, reducing the distance between an
2. ______________________ ability to respond to a stimuli.
3. ______________________ electrical signal
4. ______________________ ability to be stretched.
5. ______________________ ability to return to original position
6. ______________________ part of the muscle attached to the bone
7. ______________________ part of the muscle that moves most during a contraction; attached
to a moveable part.
8. ______________________ central portion of the muscle
9. ______________________ produces movement in a single direction
10. ______________________ produces movement in the opposite direction of another muscle
11. ______________________ accumulation causes muscle fatigue
12. ______________________ when muscles contract and shorten
13. ______________________ tension in muscle increases but muscle does not shorten
14. ______________________ muscles shrink from disuse
15. ______________________ muscles become enlarged