Lecture #11: Membrane Potentials

These flashcards cover key concepts related to membrane potentials and resting membrane potentials as discussed in Lecture #11.

What is bioelectricity?

Electrical phenomena generated by living organisms like single cells, tissues, and organs.

What constitutes the resting membrane potential?

The voltage difference between the inside and outside of a resting neuron's plasma membrane, typically around -70mV.

What are the main charge carriers in biological fluids?

Electrolytes such as Na+, K+, Cl-, and Ca²+.

What does the Nernst equation determine?

It calculates the equilibrium potential for a specific ion based on its concentration inside and outside the cell.

What is the equilibrium potential for Na+ given the extracellular concentration of 150 mM and the intracellular concentration of 15 mM?

+61.5mV.

What happens during plasma membrane depolarization?

It leads to an increase in cytosolic Ca2+, resulting in exocytosis of neurotransmitters, hormones, and muscle contractions.

What role does the sodium-potassium pump play in maintaining resting membrane potential?

It actively transports 2 K+ ions into the cell and 3 Na+ ions out, contributing to a net loss of positive charge inside the cell.

Why is the inside of a resting neuron negatively charged?

Due to the unequal distribution of ions across the plasma membrane and the activity of the sodium-potassium pump.

What causes hyperpolarization and depolarization of the membrane?

Hyperpolarization is caused by increased K+ permeability, while depolarization is caused by increased Na+ or Ca2+ permeability.

How is the final membrane voltage (Vm) calculated?

Using the Goldman-Hodgkin-Katz equation which considers the relative conductance and concentration of ions inside and outside the cell.