Actin
Troponin
Tropomyosin
Myosin
Calcium-binding site
Break the cross-bridges as a cofactor in the hydrolysis of ATP.
Bind to the troponin complex, which leads to the exposure of the myosin-binding sites.
Transmit the action potential across the neuromuscular junction.
Spread the action potential through the T tubules.
Reestablish the polarization of the plasma membrane following an action potential.
1, 2, 3, 4, 5
2, 1, 3, 5, 4
2, 3, 4, 1, 5
5, 3, 1, 2, 4
5, 3, 2, 1, 4
I only
II only
III only
I and II only
I, II, and III
Sensory neurons.
Motor neurons.
Interneurons.
Auditory neurons.
Olfactory neurons.
Dendritic region.
Axon hillock.
Axon.
Cell body.
Axon terminals.
Depolarization of the neuron.
Hyperpolarization of the neuron.
The replacement of potassium ions with sodium ions.
The replacement of potassium ions with calcium ions.
The neuron switching on its sodium-potassium pump to restore the initial conditions.
Sodium and potassium ions into the cell.
Sodium and potassium ions out of the cell.
Sodium ions into the cell and potassium ions out of the cell.
Sodium ions out of the cell and potassium ions into the cell.
Sodium and potassium ions into the mitochondria.
More slowly in axons of large than in small diameter.
By the direct action of acetylcholine on the axon membrane.
By activating the sodium-potassium pump at each point along the axon membrane.
More rapidly in myelinated than in non-myelinated axons.
By reversing the concentration gradients for sodium and potassium ions.
Prevent the hyperpolarization phase of the action potential.
Prevent the depolarization phase of the action potential.
Prevent graded potentials.
Increase the release of neurotransmitter molecules.
Have most of its effects on the dendritic region of a neuron.
No action potential will be initiated.
An action potential will be initiated and proceed only in the normal direction toward the axon terminal.
An action potential will be initiated and proceed only back toward the axon hillock.
Two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock.
An action potential will be initiated, but it will die out before it reaches the axon terminal.
Across electrical synapses.
An action potential that skips the axon hillock in moving from the dendritic region to the axon terminal.
Rapid movement of an action potential reverberating back and forth along a neuron.
Jumping from one neuron to an adjacent neuron.
Jumping from one node of Ranvier to the next in a myelinated neuron.
1 → 2 → 3 → 4 → 5
2 → 3 → 5 → 4 → 1
3 → 2 → 5 → 1 → 4
4 → 3 → 1 → 2 → 5
5 → 1 → 2 → 4 → 3
Its active transport across the presynaptic membrane.
Its diffusion across the presynaptic membrane.
Its active transport across the postsynaptic membrane.
Its diffusion across the postsynaptic membrane.
Its degradation by a hydrolytic enzyme on the postsynaptic membrane.
Act independently of their receptor proteins.
Close potassium channels.
Open sodium channels.
Close chloride channels.
Hyperpolarize the membrane.
Temporal summation.
Spatial summation.
Tetanus.
The refractory state.
An action potential with an abnormally high peak of depolarization.
Temporal summation.
Spatial summation.
Tetanus.
The refractory state.
An action potential with an abnormally high peak of depolarization.
There is a net diffusion of Na+ out of the cell.
The equilibrium potential for K+ becomes more positive.
The neuron's membrane voltage becomes more positive.
The neuron becomes less likely to generate an action potential.
The inside of the cell becomes more negative relative to the outside.
The nodes of Ranvier can conduct potentials in only one direction.
The brief refractory period prevents reopening of voltage-gated Na+ channels.
The axon hillock has a higher membrane potential than the terminals of the axon.
Ions can flow along the axon in only one direction.
Voltage-gated channels for both Na+ and K+ open in only one direction.
On the nuclear membrane
At nodes of Ranvier
On the postsynaptic membrane
On the membranes of synaptic vesicles
In the myelin sheath
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