Resting Membrane Potential & The Action Potential Flashcards

Vocabulary flashcards based on lecture notes about Resting Membrane Potential and Action Potential.

Na+/K+ ATPase

Maintains concentration gradients for both Na+ and K+ using the energy of 1 ATP molecule to pump 3 Na+ ions OUT of the cell and 2 K+ ions IN to the cell.

Resting Membrane Potential

Ion concentration gradients for Na+ and K+ at rest with the membrane permeable only to K+ through potassium leak channels.

Resting Membrane Potential

The potential energy stored across the membrane of a living cell at rest, resulting from the movement of K+ ions influenced by concentration and electrical gradients.

Resting Membrane Potential

An electrical potential difference across the membrane of all living cells at rest, measured in millivolts (mV), typically ranging from -50 mV to -100 mV.

Ion Channels

Integral membrane proteins that can be open or closed, regulating ion permeability to generate electrical signals. Some are routinely open (ion leak channels).

Ion Leak Channels

Ion channels that are always open, such as K+-leak channels, contributing to the inside-negative resting potential difference.

Chemically ('Ligand')-Gated Ion Channels

Ion channels that open when a signal molecule (e.g., ACh) binds to the channel protein.

Mechanically-Gated Ion Channels

Ion channels that open when the membrane gets stretched.

Voltage-Gated Ion Channels

Ion channels that open when the membrane potential gets less negative (depolarized).

Excitable Cells

Cells capable of changing their membrane potential to generate an electrical signal (e.g., neurons and muscle cells).

Graded Potentials

Local changes in the cell’s membrane potential that vary in size with the strength of the stimulus and are generated by chemically-gated and mechanically-gated channels.

Inhibitory Postsynaptic Potential (IPSP)

A hyperpolarizing graded potential (more negative).

Excitatory Postsynaptic Potential (EPSP)

A depolarizing graded potential (less negative).

Refractory Period

A period during which it is difficult or impossible to generate a second action potential.

Absolute Refractory Period

A period immediately following inactivation of voltage-gated Na+ channels when the membrane cannot be re-stimulated to produce another action potential.

Relative Refractory Period

A period when a new action potential can be produced, but doing so requires a larger-than-normal stimulation.