Kathleen Lonergan
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PA School Physiology Quiz on Session 2 - Neurophysiology I, created by Kathleen Lonergan on 13/06/2019.

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Kathleen Lonergan
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Session 2 - Neurophysiology I

Question 1 of 20

1

Which of the following components does NOT dictate the electrical properties of a cell membrane?

Select one of the following:

  • Ionic gradient across the cell membrane

  • Ionic channels in the cell membrane

  • Na+/K+-ATPase pump

  • Osmolarity

Explanation

Question 2 of 20

1

Which of the following ions has a greater concentration inside the cell than outside?

Select one of the following:

  • Potassium

  • Sodium

  • Chloride

  • Calcium

Explanation

Question 3 of 20

1

Which of the following ion channels has a single, straightforward function?

Select one of the following:

  • Voltage gated sodium ion channels

  • Calcium ion channels

  • Potassium ion channels

Explanation

Question 4 of 20

1

Voltage-gated sodium ion channels are responsible for generating action potentials. They will open when the membrane potential is _________ mV.

Select one of the following:

  • -50

  • -70

  • 50

  • 70

Explanation

Question 5 of 20

1

Phenytoin is a common anti-epileptic drug. Which channel does this drug block to prevent seizure activity?

Select one of the following:

  • Voltage-gated sodium ion channels

  • Voltage-gated potassium ion channels

  • Voltage-gated calcium ion channels

  • Ligand gated ion channels

Explanation

Question 6 of 20

1

Which of the following are actions of potassium ion channels? (Select all that apply)

Select one or more of the following:

  • Diversifying neuronal electrical properties

  • Diversifying temporal pattern of action potential trains

  • Dictating different responses to synaptic input

  • Intracellular signaling

Explanation

Question 7 of 20

1

What is the primary function of the voltage-gated delayed rectifier potassium ion channel?

Select one of the following:

  • Repolarizing the action potential

  • Depolarizing the action potential

  • Setting the resting membrane potential

  • Pace-making

Explanation

Question 8 of 20

1

There are four subtypes of calcium ion channels. Which of the following is NOT a primary function of the T-type channel?

Select one of the following:

  • Electrical activity of neurons for sleep

  • GI smooth muscles for motility

  • Cardiac rhythms

  • Neurotransmitter release

Explanation

Question 9 of 20

1

There are four subtypes of calcium ion channels. Which of the following is a function of the L-type channel?

Select one of the following:

  • Muscle contraction

  • Smooth muscles for gut motility

  • Intracellular signaling

  • Neurotransmitter release

Explanation

Question 10 of 20

1

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?

Select one of the following:

  • 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.

Explanation

Question 11 of 20

1

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?

Select one of the following:

  • 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.

Explanation

Question 12 of 20

1

If you have a membrane that is impermeable to both sodium and potassium ions, what is the resting membrane potential?

Select one of the following:

  • 0 mV

  • -90 mV

  • -70 mV

  • 60 mV

Explanation

Question 13 of 20

1

If you are observing a cell that is only permeable to potassium ions, what would you expect the equilibrium potential to be?

Select one of the following:

  • -90 mV

  • -70 mV

  • 60 mV

  • 0 mV

Explanation

Question 14 of 20

1

What would the membrane potential of a cell be if it were only permeable to sodium ions?

Select one of the following:

  • 60 mV

  • 90 mV

  • -90 mV

  • -60 mV

Explanation

Question 15 of 20

1

At resting conditions, we know that the membrane potential of a neuron is about -70 mV. From this value, we can conclude:

Select one of the following:

  • PK > PNa at resting conditions

  • PNa > PK at resting conditions

  • PK = PNa at resting conditions

Explanation

Question 16 of 20

1

Which of the following are involved in determining the K+ equilibrium potential of a neuron? (Select all that apply)

Select one or more of the following:

  • Na+ gradient

  • K+ gradient

  • K+ channel density

  • Membrane permeability to K+

Explanation

Question 17 of 20

1

The equilibrium potential will change if...

Select one of the following:

  • the ionic gradient changes

  • the resting membrane potential remains constant

  • sodium and potassium are moved in and out of the cell proportionately

Explanation

Question 18 of 20

1

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?

Select one of the following:

  • Action potentials will occur more easily

  • Action potentials will not occur as easily

  • There will be no change in action potential generation

Explanation

Question 19 of 20

1

The presence of leak potassium channels, which are always open:

Select one of the following:

  • 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)

Explanation

Question 20 of 20

1

What will happen to the resting membrane potential if we block half of the leak potassium ion channels in the membrane?

Select one of the following:

  • It will increase

  • It will decrease

  • It will not change

Explanation

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