Lab - Week 2 Content - Membrane Potentials Flashcards
T/F: When considering changes in charge we only need to consider what is happening inside the cell. Why?
True
Because in real life the extracellular space is so large that ionic movement has no significant effect on it’s net charge. In other words ions leaving a cell do affect the charge inside the cell but not the charge of the extracellular space which is always considered to be zero
What does Em mean/stand for?
Potential difference
What happens to the polarity of the membrane potential when only K+ channels are opened?
A set of voltage-gated potassium channels open, allowing potassium to rush out of the cell down its electrochemical gradient. These events rapidly decrease the membrane potential, bringing it back towards its normal resting state.
What happens to the polarity of the membrane potential when only Cl- channels are opened?
Because of the low Cl− concentration in cells, Cl− will normally move into the cell when the Cl− channels open. The influx of negatively charged ions then causes membrane hyperpolarization and thus inhibition of neuronal excitability.
What is hyperpolarization?
Hyperpolarization is when the membrane potential becomes more negative at a particular spot on the neuron’s membrane, while depolarization is when the membrane potential becomes less negative (more positi
What are the charges on a resting cell?
A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV, note that this number varies by neuron type and by species).
What would be the case if the KCl concentrations were switched?
The charges would be opposite with the overall charge being +70mV
