#1
Which of the following is responsible for generating action potentials in neurons?
Voltage-gated sodium channels
ExplanationThey open in response to depolarization, allowing sodium influx and initiating action potentials.
#2
What is the resting membrane potential of a typical neuron?
-70 mV
ExplanationIt represents the electrical charge difference between the inside and outside of the neuron when it's not transmitting signals.
#3
What is the function of dendrites in a neuron?
To receive incoming signals from other neurons
ExplanationThey collect and integrate signals from other neurons, transmitting them to the cell body.
#4
Which ion is primarily responsible for depolarization during the rising phase of an action potential?
Sodium (Na+)
ExplanationIts influx through voltage-gated channels leads to depolarization of the neuron.
#5
What is the role of the sodium-potassium pump in maintaining the resting membrane potential?
To pump sodium ions out and potassium ions in, generating a net negative charge inside the cell
ExplanationIt actively maintains the concentration gradients of sodium and potassium ions, crucial for resting potential.
#6
Which of the following structures is responsible for integrating excitatory and inhibitory signals in a neuron?
Axon hillock
ExplanationIt sums up the excitatory and inhibitory inputs, determining whether an action potential will be generated.
#7
Which neurotransmitter is commonly associated with inhibitory signals in the brain?
GABA (gamma-aminobutyric acid)
ExplanationIt hyperpolarizes postsynaptic neurons, reducing their likelihood to generate action potentials.
#8
What is the role of the myelin sheath in neuronal function?
To increase the speed of action potential propagation
ExplanationBy insulating the axon, it allows action potentials to 'jump' between nodes of Ranvier, speeding up transmission.
#9
What is the main function of the axon hillock in a neuron?
To initiate action potentials
ExplanationIt integrates signals from dendrites and, if the threshold is reached, initiates action potentials.
#10
What is the significance of synaptic plasticity in neural networks?
It enables learning and memory formation
ExplanationThe ability of synapses to strengthen or weaken over time allows for the storage and retrieval of information.
#11
What is the primary function of neurotransmitters?
To transmit signals between neurons
ExplanationThey are chemical messengers that carry signals across synapses from one neuron to another.
#12
What is the significance of the blood-brain barrier in neurophysiology?
To protect the brain from harmful substances circulating in the bloodstream
ExplanationIt regulates the passage of substances from the bloodstream into the brain, maintaining brain homeostasis.
#13
Which of the following is a characteristic feature of synaptic transmission?
Uni-directional communication
ExplanationSignals flow only from presynaptic to postsynaptic neurons.
#14
Which of the following is an example of a neuromodulator?
Dopamine
ExplanationIt regulates neural activity over a broader time scale, influencing functions like mood, reward, and attention.
#15
Which type of neuron carries information from the central nervous system to muscles and glands?
Motor neuron
ExplanationThey transmit signals from the brain and spinal cord to muscles and glands, controlling their activity.
#16
Which of the following structures is responsible for the reuptake of neurotransmitters from the synaptic cleft?
Reuptake transporters
ExplanationThey recycle neurotransmitters by transporting them back into the presynaptic neuron.
#17
Which of the following is an example of a neurotransmitter that acts as both an excitatory and inhibitory signal?
Glutamate
ExplanationIts effects depend on the type of receptor it binds to, leading to both excitatory and inhibitory responses.