Lesson 4 Electrical Signals and Voltage- Dependent Membrane Permeability​

What causes the resting membrane potential (RMP), and how is it defined?

results from separation of charge across the cell membrane as defined by Vm = V_in-V_out​

What is the distribution of charges on the neuronal cell membrane at rest?

the outer surface of the neuronal membrane has a cloud of positive charges, while the inner surface has a cloud of negative charges.

What maintains the separation of charge across the neuronal membrane?

the lipid bilayer, which acts as a barrier, and by the Na⁺/K⁺ pump, which actively moves ions to preserve the gradient

Why can’t ions diffuse freely across the membrane at rest?

Although a concentration gradient exists, ions cannot diffuse across the membrane because the lipid bilayer acts as a barrier; diffusion only occurs if an ion channel opens.

What is the membrane potential (Vm), and how is it defined?

it is the voltage difference across the membrane, defined as Vm=V_in−V_out

What is the typical range of the resting membrane potential (RMP) in neurons?

–60 mV to –70 mV.

What causes all electrical signaling in neurons?

they result from brief changes in the RMP, caused by ions flowing across the membrane through ion channels.