O Flashcards
What is the resting membrane potential?
The difference in electric charge across the neuron’s membrane, maintained by ion pumps.
What is the threshold of excitation?
The critical level of depolarization that must be reached for an action potential to occur.
What are the different phases of the action potential?
- Depolarization
- Repolarization
- Hyperpolarization
How do signals transmit from one neuron to another?
Through chemical synapses where neurotransmitters are released.
What is electrical excitability?
The ability of neurons to generate action potentials in response to stimuli.
What role does the sodium-potassium pump play in resting membrane potential?
It exchanges sodium ions out of the neuron and potassium ions into the neuron, using energy.
What happens during the depolarization phase of the action potential?
Sodium ions flood into the neuron, making the inside more positive.
What is the voltage at which sodium channels typically open?
-55 millivolts.
What occurs when the membrane potential reaches +40 mV?
Sodium channels close, and potassium channels remain open.
What is hyperpolarization?
The phase where the membrane potential becomes more negative than the resting potential.
What is the role of myelin sheath in neuron communication?
It insulates the axon, allowing faster action potential propagation between nodes.
True or False: Action potentials are always the same size and shape.
True.
What is the ‘all or none’ law in relation to action potentials?
Action potentials either occur fully or not at all.
What is the primary way information is coded in the brain?
Through the frequency (rate) of action potentials.
What is a chemical synapse?
A junction between two neurons where neurotransmitters are released.
What are presynaptic neurons?
Neurons that send signals to the synapse.
What are postsynaptic neurons?
Neurons that receive signals at the synapse.
What are postsynaptic potentials (PSPs)?
Changes in the membrane potential of the postsynaptic neuron in response to neurotransmitter binding.
What is an excitatory postsynaptic potential (EPSP)?
A depolarization of the postsynaptic membrane that makes it more likely to fire an action potential.
What is an inhibitory postsynaptic potential (IPSP)?
A hyperpolarization of the postsynaptic membrane that makes it less likely to fire an action potential.
Fill in the blank: Action potentials are the basis of information coding in the _______.
[nervous system].
What is the function of neurotransmitters?
To transmit signals across the synapse to the postsynaptic neuron.
What is the gap between neurons called?
Synaptic cleft.
