voltage gated ion channels Flashcards
what does it mean by equilibrium potential
the chemical and electrical gradients are equal and opposite in direction.
concentration gradient of potassium generates a _____________
efflux
electrical gradient of potassium generates a _____________
influx
increased extracellular K ____________ membrane potential
depolarises
what is the role of astrocyte
buffer potassium
What is the resting potential of a typical neuron?
-70mV
at rest the membrane is much more permeable to
potassium
what is the equilibrium potential for K
-90mV
what is the equilibrium potential for Na
+60mV
which ion allows for depolarising phase
sodium
depolarisation cause the cell to become more ?
positive
changes to membrane potential opens ?
voltage gated channels
how is gating regulated
protein conformation
what is modulation
altering the rate of a channel gating or membrane potential at which gating occurs
what type of amino acids are responsive to increase in intracellular membrane voltage
positively charged amino acids
what forms the voltage sensor
S4 helix
explain channel inactivation
ball and chain mechanism
channel protein blocks channel
which ion is responsible for repolarisation
potassium
what medical condition is a result in failure in voltage gating
epilepsy
refractory period prevents
neurones firing too rapidly and overstimulation
what is patch clamp
electrophysiological technique tha measures flow of ions
What is the IFM motif
Allows for fast inactivation of voltage gated channel
Is the ball in ball and chain mech
