Membrane Potential and Ion Dynamics in Neurons

The video explains membrane potential, the electrical charge difference across a neuron's membrane. It discusses the roles of ions like sodium, chloride, potassium, and organic anions in maintaining this potential. The resting membrane potential is around -70 millivolts, maintained by the sodium-potassium pump, which exchanges sodium and potassium ions across the membrane. Potassium ions move through ion channels until equilibrium is reached, contributing to the resting potential.

What does membrane potential refer to?

• The electrical charge of ions inside the neuron

• The difference in electrical charge between two neurons

• The difference in electrical charge between the inside and outside of a neuron

• The electrical charge of the neuron membrane

What are ions?

• Atoms that have gained or lost neutrons

• Atoms that have gained or lost electrons

• Atoms that have gained or lost protons

• Atoms with no charge

Which ions are more prevalent outside the neuron when it is at rest?

• Potassium and organic anions

• Sodium and chloride

• Calcium and magnesium

• Hydrogen and oxygen

What is the resting membrane potential of an average neuron?

• Positive 70 millivolts

• Negative 70 millivolts

• Zero millivolts

• Positive 30 millivolts

What is an anion?

• A positively charged ion

• An ion with no charge

• A neutral ion

• A negatively charged ion

What is the function of the sodium-potassium pump?

• To pump two sodium ions out and three potassium ions into the cell

• To pump three sodium ions out and two potassium ions into the cell

• To maintain a positive membrane potential

• To pump sodium ions into the cell and potassium ions out

How does the sodium-potassium pump contribute to the membrane potential?

• By equalizing the charge inside and outside the cell

• By keeping the membrane potential negative

• By making the inside of the cell more positive

• By making the outside of the cell more negative

What allows potassium ions to move across the cell membrane easily?

• Calcium pumps

• Sodium-potassium pump

• Ion channels

• Chloride channels

What happens when potassium reaches equilibrium across the membrane?

• The membrane potential becomes positive

• The membrane potential becomes zero

• The membrane potential remains at negative 70 millivolts

• The membrane potential becomes positive 70 millivolts

What is the role of ion channels in neurons?

• To allow ions to pass through the membrane

• To pump ions into the cell

• To create ions inside the cell

• To block ions from passing through the membrane