17 Questions
What is the primary condition required for the generation of an action potential?
Presence of voltage-gated Na+ and K+ channels and a strong enough graded potential
Which type of gated channel is responsible for the refractory period in a neuron?
Voltage-gated K+ channels
What is the direction of signal propagation in a neuron?
From the axon hillock to the synaptic knob
What is the effect of a neurotransmitter that affects K+ channels on the neuronal membrane potential?
Hyperpolarization of the membrane
What is the primary factor that determines the degree of depolarization in a neuron?
Concentration of the neurotransmitter
What is the minimum strength of stimulus required to generate an action potential?
The threshold potential of the neuron
During the absolute refractory period, what is the state of the Na+ ion channels?
They are closed and cannot be opened
What is the purpose of the refractory period in signal propagation?
To ensure that signals travel in one direction
What is the change in potential difference during the absolute refractory period?
A decrease from +30mV to -90mV
What is the role of the Na+K+ pump in signal propagation?
To restore the resting potential after the action potential
What is the mechanism of continuous propagation in unmyelinated neurones?
The Na+ ions attract to the negative charge on the peripherals, causing depolarization
What is the primary mechanism of saltatory conduction in myelinated neurons?
Ions jump between nodes of Ranvier
What is the average conduction velocity of somatic motor neurons in humans?
80-120 meter/s
Which type of synapse allows for bidirectional signal transmission?
Electrical synapse
What is the name of the disease that results from the immune system attacking the myelin sheath?
Multiple Sclerosis
What is the primary function of dopamine in the nervous system?
Inhibiting skeletal muscle tone
What is the term for the period during which a neuron is unable to generate another action potential?
Neuronal refractory period
Test your understanding of the all or nothing law, nerve and muscle fibre response to stimuli, and the threshold potential of neurones. Learn how the strength of the stimulus affects the response and the role of sodium ion channels in this process.
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