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- 1. Multiple Choice
What is the name of the thick myofilaments?
actin
myosin
myoglobin
tropomyosin
- 2. Multiple Choice
What is the name of the thin myofilaments in the muscle cell?
actin
myosin
troponin
collagen
- 3. Multiple ChoiceThe contractile unit of a muscle is called the __________.SarcolemmaSarcoplasmic reticulumSarcoplasmSarcomere
- 4. Multiple Choice
Number 3 represents which of the following events
action potential reaches the terminal branches
sodium rushes into the muscle fiber
calcium leaving the sarcoplasmic reticulum
ACh crossing the synapse
- 5. Multiple ChoiceContractions are generated byshortening of thick filamentsshortening of thin filamentssliding of thin filaments past thick filaments"accordian-like" folding of thick and thin filaments
- 6. Multiple Choice
Once calcium is released, it will
attach to the myosin heads
attach to receptors in the T-tubules
attach to actin receptors
attach to the troponin to expose actin receptors
- 7. Multiple Choice
The diagram represents the neuromuscular junctions. Z is pointing to which of the following?
sodium ions used to generate an impulse in the muscle fiber
calcium ions used to trigger muscle contraction
acetylcholine used to stimulate the muscle to contract
potassium ions used to repolarize the neuron
- 8. Multiple Choice
Actin is represented by number...
7
5
4
3
- 9. Multiple Choice
Which structure stores calcium in the muscle cell?
Sarcoplasm
Sarcolemma
Sarcoplasmic Reticulum
Myoglobin
- 10. Multiple Choice
When all of the sodium channels open in the muscle cell membrane, a(n) ________ is created.
negative charge
resting potential
muscle twitch
impulse
- 11. Multiple Choice
What two chemicals are necessary for muscle contraction to occur?
Sodium and Potassium
Calcium and ATP
Sodium and Phosphate
Acetylcholine and Potassium
- 12. Multiple ChoiceIdentify one factor that can cause the first sodium channel to open in a muscle cell.Calcium ions being released from the sarcoplasmic reticulum.Acetylcholine being released from the motor neuronCalcium ions binding to troponinATP causing the myosin heads to pop up.
- 13. Multiple ChoiceRegion where a motor neuron comes in close contact with a muscle cell.neurotransmittermuscular dystrophymuscle tensionneuromuscular junction
- 14. Multiple ChoiceCalcium:causes ATP binding to actinincreases the action potential along the sarcolemmabinds to proteins on myosintriggers the binding of myosin to actin
- 15. Multiple Choice
When a muscle fiber contracts, the I bands get smaller in size.
True
False
- 16. Multiple Choiceenzyme that breaks down the muscle cell neurotransmitter and ends the impulselactasesucraselipaseacetylcholinterase
- 17. Multiple Choice
Actin filaments are bound to the edges/boundaries of the sarcomere, also known as the...
M-Line
H-Zone
Z-Disc
A-Band
- 18. Multiple Choice
The muscle cell membrane is called the...
myolemma
sarcoplasm
epimyisum
sarcolemma
- 19. Multiple Choice
The energy for muscle contraction is supplied by which of the following organelles?
sacroplasmic reticulum
mitochondria
ribosomes
myosin
- 20. Multiple ChoiceConcerning the Cross Bridge Cycle, When ADP leaves the myosin head, the ________the myosin head goes into the cocked or ready positionmyosin head pulls on the actin and the sarcomere shortensThe myosin head enters the high energy state and only binds to the actin filamentthe myosin head enters the low energy state
- 21. Multiple Choice
Which of the following prevents myosin from binding to the actin in a "resting"/relaxed muscle fiber?
ATP molecules prevent calcium from binding to troponin
calcium ion block actin binding sites on the myosin heads
the troponin-tropomyosin complex covers the myosin-binding sites on the thin filaments
actin forms cross bridges with myosin, preventing tropomyosin from sliding over troponin
- 22. Multiple ChoiceA motor unit is made up of _______________.all the muscle fibers within a given musclea motor neuron and the muscle fibers it innervatesall the neurons going into an individual section of the bodya fascicle and a nerve
- 23. Multiple Choice
The H zone is represented by number...
1
2
6
7
- 24. Multiple Choice
The A band is represented by number...
1
2
5
6
- 25. Multiple Choice
Myosin is represented by number...
3
4
5
8
- 26. Multiple Choice
The I band is represented by...
4
5
6
7
- 27. Multiple Choice
Which of the following stores calcium in a muscle cell?
sarcoplasm
sarcoplasmic reticulum
myolemma
endomysium
- 28. Multiple Choice
Which of the following ends the sarcomere contraction?
calcium ions are pumped back into the SR, moving the troponin-tropomyosin complex back over the actin binding sites
sodium ions leave the muscle cell, preventing myosin from binding to actin
ACh attaches to receptors in the sarcolemma, stopping sarcomere contraction
calcium ions bind directly to the myosin heads, preventing them from attaching to the thin filaments
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