Resting and Action Potentials Flashcards
What is referred to as the charge difference from inside the cell membrane vs. outside?
membrane potential
What equation calculates the equilibrium potential?
Nernst Equation
What is the equilibrium potential of Cl-?
-70mV
What is the equilibrium potential of K+?
-90mV
What is the equilibrium potential of Na+?
+60mV
What is the equilibrium potential of Ca2+?
+130mV
Does K+ want to go into or out of the cell at resting potential?
K+ wants to leave until inside of cell -90mV.
This mechanism is responsible for pumping 3 Na+ OUT of the cell while pumping 2 K+ INTO the cell.
Na+/ K+ pump (ATPase)
What ion is the MAIN factor in RMP?
K+
During hyperkalemia, does the inside of the cells become more negative or less negative?
less negative
During hypokalemia, does the inside of the cells become more negative or less negative?
more negative
At rest, is there more K+ inside or outside the cell?
inside
At rest, is there more Na+ inside or outside the cell?
outside
What is the gap between neurons where signals are passed to one another?
synapse
Do synapses use chemical or electrical stimuli to pass information?
both
True or false- synapses can NOT be both inhibitory and excitatory
false, they can be both depending on the signal/ neurotransmitter
This occurs when positive Na+ ions rush into the cell, making it less negative
depolarization
_______ potentials weaken over distance from the source
graded
This type of signal is caused by an influx of Na+, promoting depolarization
excitatory
This type of signal is caused by the opening of Cl- channels
inhibatory
What ion is primarily responsible for depolarization
Na+ rushing in
What ion is primarily responsible for repolarization?
K+ flooding out
What ion is primarily responsible for hyperpolarization?
influx of K+ flooding out
This type of gated ion channel opens or closes in response to small voltage changes across the membrane.
voltage-gated ion channels
This principle states no matter how strong the stimulus, as long as it
is greater than the threshold, AP will occur
all-or-none principle
This period of an AP is when the cell has complete insensitivity to another stimulus, no matter its strength
absolute refractory period
This period of an AP is when a stronger than threshold stimulus can initiate another AP
relative refractory period
_______ _________ is the key in determining the direction of an AP
refractory period
What is the key factor in the velocity/ current of an AP?
The larger the fiber diameter, the faster the AP propagates
This is an insulator that speeds up the AP and allows less leakage of current
myelin sheath
True or false- APs only are propagated at the nodes of Ranvier
true
These drugs block voltage-gated Na+ channels
procaine (Novocaine)
lidocaine
cocaine
This type of summation refers to lots of signals arriving at the same time, but at different parts of the dendrite
spatial summation
This type of summation refers to repeated signals arriving at the same place which reinforces the signal
temporal summation
This is the place on the neuron that is the “first domino”
axon hillock/ trigger zone
