Muscular System

2. long, thread-like structures inside muscle cells that contain the contracting units.
5. a muscle cell found within a muscle fiber.
6. outermost connective tissue layer surrounding an entire muscle.
9. refers to the sarcoplasmic reticulum, which stores and transports calcium in muscle cells.
11. a single muscle cell.
13. the basic contractile unit of a muscle fiber.
15. a bundle of grouped muscle fibers.
17. the light or dark stripe region of a sarcomere created by overlapping filaments.
18. type of involuntary muscle found in organs like the digestive system.
19. relating to muscles and the body system responsible for movement and heat.
21. thin filament in muscle fibers that forms the light band.

1. the structural order of muscle organization from largest to smallest.
3. the cell membrane of a muscle fiber.
4. thick filament in muscle fibers that forms the dark band.
7. connective tissue surrounding each fascicle.
8. protein filaments (actin and myosin) found within myofibrils.
9. the cytoplasm (internal fluid) of a muscle cell.
10. connective tissue that separates muscles and forms tendons.
12. a sign of muscle weakness where a person uses their hands to push off their legs to stand up.
14. connective tissue surrounding each individual muscle fiber.
16. type of muscle attached to bones; voluntary and striated.
20. muscle found only in the heart; involuntary and striated.