Exam 1 Flashcards
(27 cards)
Resting potential
the net flow of all ions is zero (above and below the x-axis is the same)
Equilibrium Potential
for a specific ion, when its net flow is zero at a this voltage (where its line intersects the x-axis)
Nernst equation
Z, valence -
Xo - extracellular
X1 - intracellular
Which ion flows more at _____ .
whichever is closest to the x-axis, this one has more channels therefore more flow
If cell needs to be maintained at ____, what can do?
create a pump that pumps 1 Na+ out/ 4 K+ in ( for 10+, find voltage on X-axis and goes up or down to both ion lines)
The lipid bilayer is permeable to ____?
water - most permeable, using aquaporins
In water, ions diffuse whenever there is … ?
a nonzero temperature
Osmosis can be defined as
diffusion of water down its concentration gradient
Osmosis can be defined as
diffusion of water down its concentration gradient
When placed in distilled water the cell will…
expand
When the membrane potential is equal to the Na+ equilibrium potential, an individual ion moving through a leak channel is….
pushed by the electric field towards the more negative side
Based on our discussions, the resting potential of a cell can be defined as the membrane potential where….
the sum of Na+ and K+ flows through the membrane is zero
Diffusion of K+ ions through K+ channels requires energy…
never
The Na+/K+ pumps
maintain constant intra an extracellular K+ and Na+ concentrations
One important difference between Na+ and K+ voltage-gated channels is that….
K do not inactivate, Na do
The highest concentration of ligand-gated Na channels in a neuronal membrane is located at the …
postsynaptic site
The highest concentration of voltage-gated Na channels….
Axonal initial segment
During an action potential, the membrane potential changes as much as…
100mV
Considering that the main ions that flow during an action potential Na and K, the peak value of the action potential is limited by…..
the nernst for Na
Action potentials propagate…
in every direction, away from the location where they were initiated
The basic mechanism of action potential propagation is…
the diffusion of Na ion along the axon
In a myelinated neuron, APs cannot propagate if voltage-gated Na+ channels are..
present only at the axon hillock
Voltage-gated Ca channels are useful for synaptic transmission at this location:
presynaptic site
At synapses, Ca ion cause presynaptic vesicles to …
fuse with the presynaptic membrane to release neurotransmitter in the synaptic cleft
