Neurons and Action Potentials quiz #3 Flashcards
Neurons and Action Potentials quiz #3
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What is the function of voltage-gated sodium channels during an action potential?
Voltage-gated sodium channels open during depolarization, allowing sodium to enter and propagate the action potential. What is the function of voltage-gated potassium channels during an action potential?
Voltage-gated potassium channels open during repolarization, allowing potassium to exit and restore the resting potential. How do neurotransmitters affect postsynaptic potentials?
Neurotransmitters bind to receptors on the postsynaptic membrane, causing either depolarization (EPSP) or hyperpolarization (IPSP). What is the effect of glutamate binding to its receptors?
Glutamate binding typically causes depolarization and excitation of the postsynaptic cell. What is the effect of GABA binding to its receptors?
GABA binding typically causes hyperpolarization and inhibition of the postsynaptic cell. What is the function of acetylcholinesterase?
Acetylcholinesterase breaks down acetylcholine in the synaptic cleft, terminating its action. What is the significance of the all-or-nothing nature of action potentials?
The all-or-nothing nature ensures that action potentials are uniform in size and only occur if the threshold is reached. How do Schwann cells and oligodendrocytes differ in myelination?
Schwann cells myelinate single axons in the PNS, while oligodendrocytes myelinate multiple axons in the CNS. What is the role of the node of Ranvier in action potential propagation?
Nodes of Ranvier are sites where action potentials are regenerated due to high concentrations of ion channels. How does saltatory conduction increase the speed of action potentials?
Saltatory conduction allows action potentials to jump between nodes of Ranvier, speeding up signal transmission. What is the effect of blocking voltage-gated sodium channels?
Blocking voltage-gated sodium channels prevents action potentials from being generated or propagated. What is the function of neurotransmitter reuptake?
Neurotransmitter reuptake removes neurotransmitters from the synaptic cleft, ending the signal and recycling the molecules. What is the difference between excitatory and inhibitory neurotransmitters?
Excitatory neurotransmitters increase the likelihood of action potentials, while inhibitory neurotransmitters decrease it. What is the function of the axon terminal?
The axon terminal releases neurotransmitters into the synapse in response to an action potential. How do postsynaptic potentials summate to trigger an action potential?
Multiple EPSPs can add together (summate) to reach threshold and trigger an action potential. What is the effect of chloride ion influx on the postsynaptic membrane?
Chloride ion influx hyperpolarizes the postsynaptic membrane, causing an IPSP. What is the main function of the central nervous system?
The central nervous system integrates sensory information and coordinates responses. What is the main function of the peripheral nervous system?
The peripheral nervous system transmits signals between the CNS and the rest of the body. What is the role of interneurons?
Interneurons connect other neurons within the CNS and are the main type of neuron in the brain. What is the effect of summing EPSPs and IPSPs?
The combined effect of EPSPs and IPSPs determines whether the postsynaptic cell reaches threshold for an action potential. What is the function of the sodium-potassium pump in neurons?
It maintains ion gradients essential for resting membrane potential and action potential generation. What is the effect of acetylcholine in the parasympathetic nervous system?
Acetylcholine generally has inhibitory effects in the parasympathetic nervous system. What is the effect of norepinephrine in the sympathetic nervous system?
Norepinephrine acts as the main neurotransmitter, generally producing excitatory effects. What is the function of endorphins in the nervous system?
Endorphins suppress pain and induce feelings of euphoria. What is the effect of neurotoxins on neurons?
Neurotoxins can disrupt neuronal function by blocking ion channels or interfering with neurotransmitter signaling. What is the role of astrocytes in the nervous system?
Astrocytes are a type of glial cell that support and protect neurons, and help in neurotransmitter reuptake. What is the function of the axon in signal transmission?
The axon conducts action potentials from the cell body to the axon terminals. What is the significance of the all-or-nothing principle in action potentials?
It ensures that action potentials are uniform and only occur if the threshold is reached, providing reliable signal transmission. How do action potentials propagate along unmyelinated axons?
In unmyelinated axons, action potentials propagate continuously along the membrane. How do action potentials propagate along myelinated axons?
In myelinated axons, action potentials jump from node to node via saltatory conduction. What is the effect of increasing the frequency of action potentials?
Increasing frequency encodes a stronger or more intense signal. What is the function of neurotransmitter degradation?
Neurotransmitter degradation terminates the signal by breaking down neurotransmitters in the synaptic cleft. What is the effect of benzodiazepines on GABA-A receptors?
Benzodiazepines, like Xanax, increase the duration that GABA-A receptor channels remain open, enhancing inhibitory effects. What is the function of the presynaptic neuron?
The presynaptic neuron releases neurotransmitters to transmit a signal to the postsynaptic cell. What is the function of the postsynaptic neuron?
The postsynaptic neuron receives neurotransmitters and responds by generating postsynaptic potentials. What is the effect of serotonin on mood?
Serotonin is involved in regulating mood and feelings of happiness. What is the effect of dopamine on behavior?
Dopamine is involved in reward and reinforcement, influencing motivation and addiction. What is the function of the neuromuscular junction?
The neuromuscular junction is the synapse between a motor neuron and a muscle fiber, where acetylcholine triggers muscle contraction. What is the effect of glutamate in the central nervous system?
Glutamate acts as the main excitatory neurotransmitter, promoting action potentials. What is the effect of GABA in the central nervous system?
GABA acts as the main inhibitory neurotransmitter, reducing neuronal excitability.
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