Which of the following components does NOT dictate the electrical properties of a cell membrane?
Ionic gradient across the cell membrane
Ionic channels in the cell membrane
Na+/K+-ATPase pump
Osmolarity
Which of the following ions has a greater concentration inside the cell than outside?
Potassium
Sodium
Chloride
Calcium
Which of the following ion channels has a single, straightforward function?
Voltage gated sodium ion channels
Calcium ion channels
Potassium ion channels
Voltage-gated sodium ion channels are responsible for generating action potentials. They will open when the membrane potential is _________ mV.
-50
-70
50
70
Phenytoin is a common anti-epileptic drug. Which channel does this drug block to prevent seizure activity?
Voltage-gated sodium ion channels
Voltage-gated potassium ion channels
Voltage-gated calcium ion channels
Ligand gated ion channels
Which of the following are actions of potassium ion channels? (Select all that apply)
Diversifying neuronal electrical properties
Diversifying temporal pattern of action potential trains
Dictating different responses to synaptic input
Intracellular signaling
What is the primary function of the voltage-gated delayed rectifier potassium ion channel?
Repolarizing the action potential
Depolarizing the action potential
Setting the resting membrane potential
Pace-making
There are four subtypes of calcium ion channels. Which of the following is NOT a primary function of the T-type channel?
Electrical activity of neurons for sleep
GI smooth muscles for motility
Cardiac rhythms
Neurotransmitter release
There are four subtypes of calcium ion channels. Which of the following is a function of the L-type channel?
Muscle contraction
Smooth muscles for gut motility
The sodium-potassium ATPase pump has three main functions. It exports 3 Na+ for 2 K+ against their concentration gradients. Per action, one net positive charge moves outside of the cell. These maintain the ionic gradients and make the membrane inside the cell ~10-15 mV more negative than the outside. What is the third primary function?
Building the osmotic gradient - inducing osmosis from inside to outside the cell.
Building the osmotic gradient - inducing osmosis from outside to inside the cell.
Counteracting the osmotic gradient - inhibiting osmosis from inside to outside the cell.
Counteracting the osmotic gradient - inhibiting osmosis from outside to inside the cell.
In some individuals, red blood cells (RBCs) express a high density of Na/K-ATPases to counteract the unusually high permeability of the membrane to Na+. When these RBCs reach and are delayed in the vein of the spleen, what would happen to these RBCs?
They may swell and rupture.
They may shrink in volume.
They may decrease in membrane potential (membrane inside the cell becomes more negative)
They may increase in intracellular potassium.
If you have a membrane that is impermeable to both sodium and potassium ions, what is the resting membrane potential?
0 mV
-90 mV
-70 mV
60 mV
If you are observing a cell that is only permeable to potassium ions, what would you expect the equilibrium potential to be?
What would the membrane potential of a cell be if it were only permeable to sodium ions?
90 mV
-60 mV
At resting conditions, we know that the membrane potential of a neuron is about -70 mV. From this value, we can conclude:
PK > PNa at resting conditions
PNa > PK at resting conditions
PK = PNa at resting conditions
Which of the following are involved in determining the K+ equilibrium potential of a neuron? (Select all that apply)
Na+ gradient
K+ gradient
K+ channel density
Membrane permeability to K+
The equilibrium potential will change if...
the ionic gradient changes
the resting membrane potential remains constant
sodium and potassium are moved in and out of the cell proportionately
You have a patient in kidney failure. They are not regulating K+ ions in the extracellular fluid. As a result, the extracellular K+ level has increased from 5 mM to 15 mM. How would this affect brain function?
Action potentials will occur more easily
Action potentials will not occur as easily
There will be no change in action potential generation
The presence of leak potassium channels, which are always open:
Drives the membrane potential towards the potassium equilibrium potential (-90 mV)
Drives the membrane potential towards the potassium equilibrium potential (-70 mV)
Drives the membrane potential towards the sodium equilibrium potential (-90 mV)
Drives the membrane potential towards the sodium equilibrium potential (60 mV)
What will happen to the resting membrane potential if we block half of the leak potassium ion channels in the membrane?
It will increase
It will decrease
It will not change
