Bioelectricity, electrical signals, and neural communication Flashcards
resting potential
electrical potential difference that exists across the plasma membrane of every cell in the body
Average resting potential of neuron
-70mV
resting potential is a steady-state equlibrium that develops because
unequal distribution and permeability to key ions
ICF
low Na+, high K+, low Cl- (slightly negative)
ECF
high Na+, low K+, high Cl- (slightly positive)
flux
moving something across a membrane
transmembrane flux of an ion through an open ion channel is due to
electrochemical potential of that ion
what causes unequal distribution of ions–leading to an electrochemical potential developing?
mostly caused by primary active transport–Na+/K+
two influences on ions
electrical and chemical
Nernst equilibrium potential (reversal potential)
the membrane potential that would bring about electrochemical equilibrium of a cell if it were only permeable to one ion species
electrochemical equilibrium
steady-state condition in which there is NO NET ionic flux. the two driving forces, electrical and chemical, cancel each other out
electromotive force is
equal in magnitude by opposite in direction of the diffusional force
The nernst equation provides
boundaries. it gives you the extremes, and the cell will be somewhere between the extremes
Equilibrium potential of K+
K+= -90mV
Equilibrium potential of Na+
Na+ = +60mV
eq potential of Ca2+
Ca2+ = +130mV
eq potential of Cl-
Cl- = -86mV
under normal resting conditions, the membrane is about 30x more permeable to ___ than ___
K+ (-90mV) than Na+ (+60mV)
Vm=resting potential of the cell
Vm= -70mV
more permeable a cell is to a particular ion
the more influence the ion has on resting potential–K+ has a much bigger influence on resting potential than Na+
Goldman Eqn
resting membrane potential–steady-state condition in which there is not net ionic flux. Accounts for the permeability of ALL relevant ion species
Excitable cells
utilize electrical signals to integrate and transmit information
graded potentials
local and non-propagated electrical signals
action potentials
self-propagating electrical signals
depolarization
upshoot, more positive than resting
repolarization
going back towards resting
hyperpolarization
more negative than resting (refractory period)
receptive segment of neuron
where stimulus input is recieved and transduced into local graded potentials
