Question
identify and descibe what is occuring at events 1-4 in diagram action potential shown
Answers
GPT 3.5
Without a specific diagram to refer to, I can provide a general description of events occurring during an action potential.
1. Resting State: The neuron is at its resting membrane potential, which is usually around -70 millivolts. At this state, the neuron is polarized, meaning there is a difference in electrical charge between the inside and outside of the neuron.
2. Depolarization: When stimulated, the neuron undergoes depolarization. This means that the membrane potential becomes less negative (towards zero) and the inside of the neuron becomes more positive due to the influx of positively charged ions, particularly sodium ions (Na+). This is facilitated by the opening of voltage-gated sodium channels on the neuron's membrane.
3. Threshold and Action Potential: Once the membrane potential reaches a threshold level (around -55 millivolts), an action potential is triggered. At this point, voltage-gated sodium channels open completely, allowing a rapid influx of sodium ions into the neuron. This causes a rapid change in membrane potential from negative to positive, and the neuron becomes depolarized.
4. Repolarization: After reaching its peak positive potential, the neuron begins repolarization. Voltage-gated sodium channels close, and voltage-gated potassium channels open, allowing potassium ions (K+) to move out of the neuron. This causes the membrane potential to become more negative again, restoring the original polarity. This repolarization phase is crucial for the neuron to return to its resting state and be ready for the next action potential.
1. Resting State: The neuron is at its resting membrane potential, which is usually around -70 millivolts. At this state, the neuron is polarized, meaning there is a difference in electrical charge between the inside and outside of the neuron.
2. Depolarization: When stimulated, the neuron undergoes depolarization. This means that the membrane potential becomes less negative (towards zero) and the inside of the neuron becomes more positive due to the influx of positively charged ions, particularly sodium ions (Na+). This is facilitated by the opening of voltage-gated sodium channels on the neuron's membrane.
3. Threshold and Action Potential: Once the membrane potential reaches a threshold level (around -55 millivolts), an action potential is triggered. At this point, voltage-gated sodium channels open completely, allowing a rapid influx of sodium ions into the neuron. This causes a rapid change in membrane potential from negative to positive, and the neuron becomes depolarized.
4. Repolarization: After reaching its peak positive potential, the neuron begins repolarization. Voltage-gated sodium channels close, and voltage-gated potassium channels open, allowing potassium ions (K+) to move out of the neuron. This causes the membrane potential to become more negative again, restoring the original polarity. This repolarization phase is crucial for the neuron to return to its resting state and be ready for the next action potential.