Neuronal Action Potential Concepts

The video tutorial explains nerve impulses and membrane potential, focusing on ion movement, resting potential, action potential, and repolarization. It describes how sodium and potassium ions contribute to these processes and how local currents and refractory periods ensure impulses move in one direction. Practice questions are provided for revision.

What is the primary factor that influences the movement of ions across a membrane?

• Concentration gradient

• Temperature

• Ion size

• Membrane thickness

During the resting potential, what is the charge inside the neuron?

• Positive 70 millivolts

• Negative 17 millivolts

• Positive 17 millivolts

• Negative 70 millivolts

How many sodium ions are pumped out of the neuron during resting potential?

• Four

• Three

• Two

• One

What triggers the opening of sodium voltage-gated channels during depolarization?

• A change in pH level

• A decrease in temperature

• The presence of potassium ions

• An electrical signal above the threshold potential

What is the typical voltage range during depolarization?

• Negative 40 to 30 millivolts

• Positive 30 to 40 millivolts

• Negative 70 to 75 millivolts

• Positive 70 to 75 millivolts

During repolarization, which ions diffuse out of the neuron?

• Potassium ions

• Calcium ions

• Chloride ions

• Sodium ions

What is the voltage during repolarization?

• Positive 30 millivolts

• Positive 75 millivolts

• Negative 75 millivolts

• Negative 30 millivolts

What is the term for the process by which nerve impulses travel along neurons?

• Local currents

• Axonal drift

• Neuronal shift

• Impulse cascade

Why do nerve impulses only travel in one direction?

• Because of ion size

• Due to temperature changes

• Because of membrane thickness

• Due to the refractory period

What prevents depolarization from moving backward?

• The temperature of the neuron

• The presence of calcium ions

• The refractory period

• The thickness of the axon