resting action potentials Flashcards
a. Explain the ionic permeability of the resting cell membrane and the factors influencing ionic distribution across the cell membrane
In neurons and their surrounding fluid, the most abundant ions are:
High conc inside : k+ (150 mM)
Low conc : Cl- (5 mM) and Na + (15 mM)
Cell membranes at rest:
Fairly readily permeable to K+ and Cl-
Poorly permeable to Na+
Impermeable to various large organic anions
Two fundamental properties of cells give rise the resting membrane potential:
Selective permeability of the cell membrane (PK»_space; PNa)
Unequal distribution of ions across membrane (maintained by Na+/K+ pump)
b. Explain how voltage-controlled ion channels regulate membrane conductance
describe the current and voltage changes during the action potential in excitable cells
