Muscle Crossword

2. A bundle of muscle fibers that run parallel to each other within a skeletal muscle
4. A thin layer of connective tissue that surrounds each muscle fiber
5. The connective-tissue coverings that surround a muscle and form coverings for the bundles of muscle fibers
6. The main contractile unit of muscle fiber in the skeletal muscle
10. A light band in skeletal muscle cells that contains thin actin filaments
12. The ability of muscle cells to forcefully shorten
15. A protein found in cells that helps with cell movement, cell shape, and muscle contraction
16. The ability of a muscle to be stretched or extended
17. Junction A synaptic connection between the terminal end of a motor nerve and a muscle
19. Unit A single motor neuron (nerve cell) and all the muscle fibers it directly controls
20. A rod-shaped organelle in muscle cells that is responsible for muscle contraction

1. A neurotransmitter that plays a role in memory, learning, attention, arousal, and involuntary muscle movement
3. The ability of muscle fibers to respond to stimuli by generating electrical impulses
7. A protein band that marks the boundary between adjacent sarcomeres in a muscle fiber
8. The central region of the A band within the sarcomere which does not contain thin (actin) filaments
9. A layer of dense connective tissue that surrounds the entire muscle
11. A protein found in cells that helps with cell movement, cell shape, and muscle contraction
13. A dark region of a muscle fiber that contains thick myosin filaments and some thin actin filaments
14. A fibrous connective tissue that attaches muscle to bone
18. The ability of a muscle to return to its original length after being stretched or shortened