18 Questions
What happens to the voltage-gated Na+ channels after the threshold is reached?
They open immediately
What is the primary function of the Na+-K+ pump?
To regulate the concentration of sodium and potassium ions
What happens to the 'upstream' part of the membrane after an action potential occurs?
It enters its refractory period
During the repolarization phase of an action potential, which ions move out of the cell?
Potassium ions only
What is the term for the process by which an action potential jumps from one node of Ranvier to the next in a myelinated axon?
Saltatory conduction
What is the maximum frequency of action potentials limited by?
The refractory period of the neuron
What is the direction of propagation of an action potential along the cell membrane?
Unidirectional
What is the purpose of the myelin sheath in the propagation of an action potential?
To allow the action potential to occur only at the nodes of Ranvier
What happens when an action potential reaches the end of an axon?
It is transmitted to a neighboring neuron
What is the characteristic of an action potential that describes it as an 'all-or-none' response?
The action potential has a fixed amplitude and duration
What is the term for the connection between two different neurons where the action potential is transmitted?
Synapse
What is the result of a thicker myelin sheath on the propagation of an action potential?
It increases the speed of the action potential
What occurs when the membrane potential depolarizes to threshold along the axon of a neuron?
An action potential will occur
What is the main reason why an action potential does not travel backwards?
The flow of positive charge only occurs in one direction
During the refractory period, what is true about the affected part of the membrane?
It is not sensitive to new stimuli and cannot generate another action potential
What is the primary role of sodium ions in generating an action potential?
To depolarize the membrane
What is the characteristic of an action potential that makes it an 'all or none' event?
It is an all-or-none event, meaning it either occurs completely or not at all
What is the purpose of the trigger zone in a neuron?
To start the action potential at one end of the neuron
Understand the continuous propagation of an action potential, including the refractory period and the role of myelination in speeding up the process. Explore the mechanisms of AP propagation along myelinated axons.
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