3 Neuron Structure and Function

What is the function of ion channels in a neuron?

• To generate action potentials

• To maintain the resting potential

• To regulate the concentration of ions

• To transmit signals between neurons

What is the main force that drives ions to move across the neuronal membrane?

• Concentration gradient

• Electrical potential

• Both concentration gradient and electrical potential

• None of the above

What triggers the opening of voltage-gated ion channels?

• Changes in the local environment of the membrane

• Binding of specific molecules to the channel

• Changes in the membrane potential

• All of the above

What is the main example of active transport in a neuron?

• Sodium-potassium pump

• Potassium leak channels

• Voltage-gated ion channels

• Ligand-gated ion channels

What is the resting potential of most neurons?

• -60 to -80mV

• -30 to -40mV

• 0mV

• +30 to +40mV

What is the equilibrium potential for potassium?

• -60 to -80mV

• -30 to -40mV

• 0mV

• +30 to +40mV

What triggers the initiation of an action potential?

• Light or darkness falling onto the retina

• Sound waves

• Inputs from other neurons

• All of the above

What happens to voltage-gated sodium channels during the rising phase of an action potential?

• They open and allow sodium to enter the cell

• They close and prevent sodium from entering the cell

• They become inactivated and cannot open

• They become activated and allow potassium to leave the cell

What is the role of voltage-gated potassium channels during the falling phase of an action potential?

• They open and allow potassium to enter the cell

• They close and prevent potassium from leaving the cell

• They become inactivated and cannot open

• They become activated and allow sodium to enter the cell

What is the purpose of the myelin sheath in the conduction of action potentials?

• To slow down the conduction of action potentials

• To insulate the axon and speed up the conduction of action potentials

• To prevent the conduction of action potentials

• To regulate the concentration of ions