Nerve Action Potential Quiz

The local response is characterized by decreased excitability

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The firing level of a stimulated nerve fiber is reached at a membrane potential of -65 mV.

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The ascending limb of nerve action potential curve is represents repolarization.

• Represents repolarization

• Represents depolarization

• Due to slow 1C outflow

• Due to Ca+ inflow

During the activation of a nerve cell membrane, CL ions flow outward.

• CL ions flow outward

• K+ ions flow inward

• Na+ ions flow outward

• Na+ ions flow inward

During depolarization, K+ ions diffuse outside.

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Repolarization of nerve is caused by opening of voltage gated sodium channels.

• Sodium channels

• Calcium channels

• Chloride channels

• Potassium channels

Concerning the voltage gated sodium channels: a- The activation gate for sodium are closed at rest.

• The activation gate for sodium are closed at rest

• The inactivation gate for sodium are closed at rest

• At the firing level, the inactivation channels are closed

• None of the above

After release from the neuromuscular junction, acetylcholine activates presynaptic potassium channels.

• Activates presynaptic potassium channels

• Causes postsynaptic depolarization

• Enters the sarcoplasmic reticulum

• Is triggered by acetylcholinesterase

In muscle tissue, neurotransmitter receptors are located in synaptic vesicles.

• In synaptic vesicles

• On the motor neuron axon terminals

• In the synaptic cleft

• On the motor end plate

The action potential of skeletal muscle has a prolonged plateau phase.

• Has a prolonged plateau phase

• Spreads inwards to all parts of the muscle via T tubules

• Is longer than the action potential of cardiac muscle

• Is not essential for muscle contraction