Action Potentials

Front

What is the resting potential of a neuron?

Back

The resting potential is the electrical charge difference across the neuron's membrane when it is not actively transmitting a signal, typically around -70 mV.

Front

What occurs during the depolarization phase of an action potential?

Back

During depolarization, sodium channels open, allowing Na+ ions to flow into the neuron, causing the membrane potential to become more positive.

Front

What is hyperpolarization in the context of action potentials?

Back

Hyperpolarization is the phase where the membrane potential becomes more negative than the resting potential, often due to the efflux of K+ ions.

Front

What is the threshold potential?

Back

The threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential, typically around -55 mV.

Front

What charge does the inside of the axon have at the peak of the action potential?

Back

At the peak of the action potential, the inside of the axon has a positive charge due to the influx of Na+ ions.

Front

What role do sodium (Na+) ions play in action potentials?

Back

Sodium ions are crucial for depolarization; their influx through voltage-gated channels leads to the rapid rise in membrane potential during an action potential.

Front

What is the role of potassium (K+) ions during an action potential?

Back

Potassium ions help restore the resting potential by flowing out of the neuron during repolarization and hyperpolarization phases.

Front

Define the term 'action potential'.

Back

An action potential is a rapid, temporary change in the membrane potential of a neuron that allows for the transmission of electrical signals along the axon.

Front

What is the all-or-nothing principle in action potentials?

Back

The all-or-nothing principle states that once the threshold potential is reached, an action potential will occur fully; it does not vary in strength.

Front

What is the refractory period?

Back

The refractory period is the time following an action potential during which a neuron is less responsive to stimuli, ensuring unidirectional signal propagation.