30 Questions
What is the value of the resting membrane potential in a neuron?
-70 mV
What is the main reason for the electrical polarization of the plasma membrane in a resting neuron?
More potassium leak channels than sodium leak channels
What is the role of trapped anions in the resting membrane potential?
They cannot follow potassium ions out of the neuron
What are the two factors that determine the membrane potential?
Ion concentration gradient and ion permeability
What is the state of the neuron when the resting membrane potential is measured?
Inactive and not transmitting a signal
What is the term for the electrical polarization of the plasma membrane in a resting neuron?
Electrical polarization
What is the direction of an action potential in a neuron?
Unidirectional
What is the purpose of the myelin sheath in saltatory conduction?
To act as a good electrical insulator
What is the effect of lower temperature on the speed of nerve impulses?
It slows down the speed
What is the advantage of electrical synapses in neuronal communication?
Faster communication and synchronization
What is the location of voltage-gated ion channels in a myelinated axon?
Nodes of Ranvier
What determines the speed of nerve impulses in an axon?
Temperature, axon diameter, and myelin sheath
What is the main function of the presynaptic neuron in a chemical synapse?
To convert an electrical signal into a chemical signal
What is the result of an excitatory synapse on the postsynaptic cell?
It depolarizes the local membrane potential of the postsynaptic cell
What is the relationship between the strength of the stimulus and the frequency of action potentials?
The frequency of action potentials increases as the stimulus strength increases until a maximum frequency is reached.
Where are neurotransmitters synthesized in the neuron?
In the cytoplasm of the cell body
What is the sequence of events in an action potential?
Depolarization, repolarization, refractory period, and after-hyperpolarization.
What is the function of the synaptic cleft in a chemical synapse?
To separate the presynaptic and postsynaptic neurons
What is the result of an inhibitory synapse on the postsynaptic cell?
It hyperpolarizes the local membrane potential of the postsynaptic cell
During which phase of the action potential is the membrane potential restored to the resting state?
Repolarization phase
What is the role of neurotransmitters in a chemical synapse?
To act as chemical messengers between neurons
What is the function of the sodium-potassium pump in the action potential process?
To restore the initial ionic condition after repolarization
What is the result of the action potential on the adjacent portions of the membrane?
The action potential causes an electric current that stimulates adjacent portions of the membrane.
What is the duration of the absolute refractory period?
From the beginning of the action potential until the end of repolarization
What is the function of the electrogenic Na+–K+ ATPase in terms of ion transport?
It expels 3 Na+ ions for every 2 K+ ions imported
What is the characteristic of a graded potential in terms of its spatial extent?
It is confined to a localized region of the plasma membrane
What is the significance of the threshold stimulus in generating an action potential?
It is necessary for the generation of an action potential
What is the difference between graded potentials and action potentials in terms of summation?
Graded potentials can summate, but action potentials cannot
What is the location where an action potential is primarily generated?
Neuron axons
What is the sequence of events during an action potential?
Depolarization followed by repolarization
Test your knowledge of the nervous system with this quiz on neurophysiology! Topics include the physiological basis of resting membrane potential, types of membrane potentials, action potential generation, and synaptic transmission. Learn and practice with these questions!
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