How do calcium ionsparticipate in musclecontraction? Why do bothmuscle contraction andmuscle relaxation spendenergy?

The muscle relaxes if no new nerve signal arrives. However the neurotransmitter from the previous stimulation is still present in the synapse The activity of helps to remove this neurotransmitter. myosin action potential tropomyosin acetylcholinesterase

Every skeletal muscle fiber is supplied by a motor neuron at the NMJ. Watch this video (http://openstaxcollege.org/l/skelmuscfiber) to learn more about what happens at the neuromuscular junction. (a) What is the definition of a motor unit? (b) What is the structural and functional difference between a large motor unit and a small motor unit? Can you give an example of each? (c) Why is the neurotransmitter acetylcholine degraded after binding to its receptor?

Nerve impulses first stimulate a skeletal muscle fiber at _______. a. T tubules b. sarcomeres c. neuromuscular junctions d. actin binding sites

Figure 38.37 Which of the following statements about muscle contraction is true? The power stroke occurs when ATP is hydrolyzed to ADP and phosphate. The power stroke occurs when ADP and phosphate dissociate from the myosin head. The power stroke occurs when ADP and phosphate dissociate from the actin active site. The power stroke occurs when Ca2+ binds the calcium head.

What are the structural and functional differences between slow and fast muscle?

Smooth muscles differ from skeletal and cardiac muscles in that they ________. lack myofibrils are under voluntary control lack myosin lack actin

What factors contribute to the amount of tension produced in an individual muscle fiber?

Cardiac muscles differ from skeletal muscles in that they ________. are striated utilize aerobic metabolism contain myofibrils contain intercalated discs

The _____ is the basic unit of muscle contraction. a. myofibril b. sarcomere c. muscle fiber d. myosin filament