Exploring Neuron Action Potential Mechanisms

The video explains how action potentials are generated and conducted along the axon. It covers the role of different ion channels, including leak and voltage-gated channels, in the process. The video details the phases of action potential, including the rising and falling phases, and the refractory period, highlighting the importance of sodium and potassium ions in these processes.

What is the role of the trigger zone in action potentials?

• It is where action potentials are initiated.

• It is responsible for neuron repair.

• It stores ions for the neuron.

• It generates neurotransmitters.

Which type of ion channel is always open and not gated?

• Leak channels

• Voltage-gated sodium channels

• Ligand-gated ion channels

• Voltage-gated potassium channels

What happens when the membrane potential crosses the threshold value?

• Leak channels close.

• Potassium ions enter the neuron.

• Voltage-gated sodium channels open.

• The neuron stops functioning.

What is the typical resting membrane potential of many neurons?

• Positive 40 millivolts

• Positive 50 millivolts

• Negative 50 millivolts

• Negative 60 millivolts

During the rising phase of the action potential, what causes the membrane to depolarize?

• Calcium ions entering the neuron

• Sodium ions entering the neuron

• Sodium ions leaving the neuron

• Potassium ions entering the neuron

Why does the action potential usually peak around positive 40 millivolts?

• The neuron runs out of sodium ions.

• Potassium channels open at this point.

• Sodium channels close automatically at higher potentials.

• The membrane becomes impermeable.

What causes the falling phase of the action potential?

• Potassium ions exiting the neuron

• Sodium ions entering the neuron

• Calcium ions entering the neuron

• Chloride ions entering the neuron

Which channels are slower to open and close compared to voltage-gated sodium channels?

• Voltage-gated potassium channels

• Ligand-gated ion channels

• Calcium channels

• Leak channels

What is the refractory period?

• A period when the neuron is hyperactive

• A period when the neuron is depolarized

• A period when it is difficult or impossible to trigger another action potential

• A period when the neuron is at rest

Why do action potentials travel in one direction from the trigger zone to the axon terminals?

• Because the axon terminals generate action potentials

• Because the trigger zone is impermeable

• Because the membrane behind the action potential is refractory

• Because ions can only move in one direction