Resting potential Flashcards
What is flux?
Number of molecules that cross a unit area per unit time
In dynamic equilibrium there is no net flux
What is voltage?
Generated by ions to produce a charge gradient - potential difference
What is current
Movement of ions due to a potential difference
What is resistance?
Barrier that prevents movement of ions
What is the resting membrane potential
Found in all cells ~70mV in nerve cells
What is an ion channel?
A pore that allows for gating (can open or close in response to ligands, mechanical or for trans membrane voltage
What is the electrochemical equilibrium
Movement of ions balance between concentration gradient and electrical gradient, where flow down c-gradient offset by opposite movement caused by ion like repulsion
What is the equilibrium potential?
Potential where the electrochemical equilibrium has been released, it is the potential that prevents diffusion of the ion down it’s concentration gradient
What is the neurone membrane permeable to even at rest?
Slightly to Cl- and Na+
so membrane affected by conc gradients and permeability
What is the goldman hodgkins katz equation used for?
Estimating the membrane potential considering the permeability and concentration gradients of K+/Na+/Cl-
What happens to membrane potential in depolarising,
hyperpolarising,
overshoot,
repolarising
Depolarising: potential more positive
hyperpolarising: potential more negative
overshoot: potential more positive
repolarising: return to resting membrane potential
What is a graded potential?
Change to membrane potential in response to stimulation, often occurring at synapses to integrate a number of signals and produce a response proportional to stimuli - can initiate or prevent action potentials
What is graded decay?
Strength of impulse decreases as travel along axon
