Muscle Anatomy Crossword - Answer Key

ACROSS

2. section of a myofibril from one Z line to the next Z line - sarcomere
4. bundle of muscle fibers - fascicle
8. theory that explains how muscle contraction works; sliding __ theory - filament
11. Outermost layer, surrounds entire muscle - epimysium
14. describes muscles that are striped in appearance - striated
16. muscle fiber membrane - sarcolemma
17. space between a neuron and the muscle, synaptic ___ cleft
20. overlapping patterns of actin and myosin; I and A ___ bands
22. membranous channels that surround the myofibrils; sarcoplasmic ___ - reticulum
23. when muscles become tired - fatigue
24. type of muscle found in the digestive tract, involuntary - smooth
25. type of muscle that makes up the heart - cardiac

DOWN

1. helps regenerate ATP, ___ phosphate - adenosine
3. thick filaments of a muscle fiber - myosin
5. type of muscle that connects to bones, voluntary - skeletal
6. store neurotransmitters - vesicles
7. neurotransmitter used to cause muscle contraction - acetylcholine
9. connects muscles to bones - tendons
10. individual muscle fiber - myofibril
12. organelle that provides the energy needed for muscle contraction - mitochondria
13. connects bones to other bones - ligaments
15. surrounds fascicles - perimysium
18. thin filaments of a muscle fiber - actin
19. minimal level of stimulus to cause a contraction - threshold
21. this superhero has huge muscles when he's angry; David Banner - Hulk