Explain why the inside of the membrane changes form a jet negative charge to a positive charge at the peak of the action potential and then back to a net negative charge after the action of potential.

Explain the contribution of the Na+/K+ pump activity to the genesis and maintenance of the resting membrane potential and indicate which category of membrane transport the Na+/K+ pump belongs to

If: membrane potential=-70mV, ENa=+60mV, and Ex=-90mV, consider which directions Na+ and K+ will leak across the membrane. If both ions are crossing the membrane, what is the most important factor in determining whether membrane potential will become more positive or more negative?

Consider the brain and spinal neurons. If you bathed a resting neuron with an excess of potassium ions (for example, more than 40 times higher than normal), what would be the effect on resting membrane potential?

Explain the following; If a drug partly blocks a membrane’s potassium channels, how              does it affect the action potential? Suppose the threshold of a neuron were the same as the neuron’s resting potential. What would happen? At what frequency would the cell produce action potentials?

A change in membrane potential which is due to ion influx or efflux in a single region with the ions then diffusing away from that region is called a(n) ______

The membrane potential caused by differences in ions across the plasma membrane of an electrically excitable cell (when not stimulated) is called:     action potential     resting membrane potential     graded potential     local potential

There are differences in Na+, K+, and Cl- ion concentrations across the membrane.  Knowing that ions like to flow down their respective concentration gradients explain how the movement of Cl- and K+ ions can result in membrane hyperpolarization.

Ions like K+ cannot diffuse directly across the membrane. They need open ion channels to cross the membrane. Explain why.

Match each type of membrane potential (resting, threshold, graded, or action) to its definition: a) The membrane potential at which voltage gated sodium channels open. b) The membrane potential that triggers the action potential. c) Change in membrane potential that may or may not reach threshold and that may be depolarizing or hyperpolarizing. d) Rapid, strong depolarization followed by immediate repolarization. This potential is self-renewing if the right ion channels are nearby.