Amaze Writers

After nervous stimulation stops, what prevents acetylcholine in the synaptic cleft from continuing to stimulate contraction?”

1. calcium ions returning to the terminal cisternae
2. the tropomyosin blocking the myosin once full contraction is achieved
3. acetylcholinesterase destroying the acetylcholine

During the repolarization phase of an action potential a small region of the inner surface of a muscle cell’s membrane becomes more _________.

1. negative as potassium diffuses into the cell
2. positive as potassium diffuses into the cell
3. negative a potassium diffuses out of the cell
4. positive as sodium diffuses out of the cell

A electrical impulse travels deep into the muscle fiber along

1. the sarcolemma
2. T-tubule membranes
3. the endomysium
4. myofibrils

When stimulated by a muscle impulse, what do the terminal cisternae release into the sarcoplasm?”

1. “sodium ions, Na+”
2. “calcium ions, Ca2+”
3. “adenosine triphosphate, ATP”
4. “acetylcholine, ACh”

Which of the following is the correct sequence of events for muscle contractions?

1. “action potential in neuron, neurotransmitter release, muscle cell action potential, release of calcium ions from sacroplasmic reticulum, ATP-driven power stroke, sliding of myofilaments”
2. ” neurotransmitter release, muscle cell action potential, action potential in neuron, release of calcium ions from sarcoplasmic reticulum, sliding of myofilaments, ATP-driven power stroke”
3. ” action potential in neuron, neurotransmitter release, release of calcium ions from sarcoplasmic reticulum, muscle cell action potential, ATP-driven power stroke”
4. “neurotransmitter release, release of calcium ions from sarcoplasmic reticulum, muscle cell action potential, sliding of myofilaments, ATP-driven power stroke”

In excitation-contraction coupling the excitation refers to the____.

1. bond that actin head groups must form with myosin before a contraction can occur
2. action potential traveling along the muscle cell membrane
3. excitation of the sarcoplasmic reticulum that triggers the release of ATP.
4. ALL OF THE ABOVE