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Across 1. Sudden, involuntary contraction of muscles 3. High endurance muscle with lots of mitochondria 8. Type of smooth muscle with few gap junctions that contract independently of each other 9. By-product of anaerobic respiration 11. Type of respiration with net yield of 2ATP 12. Hollow cylinders between smooth muscle cells which permit movement of action potentials 16. Type of smooth muscle with many gap junctions that tends to contract rhythmically as a unit 18. Type of filament found in smooth muscle which act as the Z disc 20. Type of contraction when muscle changes length to move a load 21. Type of respiration where oxygen is used 22. Because smooth muscle cells do not have striations, they do not have ____________ 23. For muscles to work, they must be attached to a ___________ object

Down 1. Molecule stored in muscles, which is used to phosphorylate ADP for energy 2. The molecules which anaerobic respiration splits glucose into 4. Type of respiration with net yield of 36ATP 5. Swellings in the axons surrounding smooth muscle cells which form the motor units 6. Resistance to movement in opposition to the force 7. Low endurance muscle with few mitochondria 10. Alternating contractions which move substances down a tube 13. Type of respiration where oxygen is not used 14. Type of contraction when muscle does not change length to hold something in place 15. Ability of smooth muscle cells to divide and reproduce 17. Force generated by a contracting muscle on some object 19. Occurs when muscles are physiologically unable to contract