Lesson Worksheet: The Nerve Impulse Biology

In this worksheet, we will practice explaining how a resting potential is maintained and describing the electrical and chemical changes that occur during an action potential.

Q1:

All the following ions are involved in the propagation of nerve impulses in the axon of one neuron except  ions.

  • Apotassium
  • Bchloride
  • Csodium
  • Dcalcium

Q2:

In neurons at resting potential, the concentration gradient of positively charged sodium ions and potassium ions would dictate that sodium ions move into the cell and potassium ions move outside the cell. How do neurons maintain the ion distribution across their membrane despite that?

  • ABy means of Na+/Cl pumps
  • BBy means of positively charged membrane proteins
  • CBy means of Na+/K+ pumps
  • DBy means of voltage-gated Na+ channels
  • EBy means of Cl channels

Q3:

The speed of nerve impulse is equal in all of the following parts of the nerve cell except in .

  • Athe myelinated axon
  • BRanvier’s node
  • Cthe part of the axon with the Schwann cell
  • DThe statement is wrong; the speed of nerve impulse is equal in all of the above.

Q4:

The repolarisation of neurons is one of the phases of an action potential. Which of the following best describes the repolarisation phase?

  • AIt is the phase when sodium ion channels open and sodium ions flow back to the outside of the cell.
  • BIt is the phase when sodium ion channels close and potassium flows out of the cell.
  • CIt is the phase when chloride ions flow out of the cell and sodium ions flow into the cell.
  • DIt is the phase when sodium ion channels open and the sodium flows into the cell.

Q5:

Which of the following statements about nerve impulses is true?

  • ANerve impulses are divided into weaker impulses when transmitted to multiple neurons at once.
  • BNerve impulses start strong and degrade while propagating down the axon.
  • COnly a stimulus with sufficient strength can produce an action potential in neurons.
  • DNeurons amplify weak stimulations in order to be able to produce an action potential.

Q6:

Which of the following is the phase during which the neuron becomes unable to generate a second action potential regardless of stimulus strength?

  • ARepolarisation phase
  • BDepolarisation phase
  • CResting state
  • DRefractory period

Q7:

Hyperkalemia is an abnormally elevated level of potassium in the blood. Which of the following effects will the hyperkalemia most likely have on the resting membrane potential of a neuron?

  • ADue to the high concentration of the extracellular potassium, the outflow of potassium and the resting potential will increase, causing a prolonged repolarisation state.
  • BDue to the high concentration of the extracellular potassium, the outflow of potassium and the resting potential will decrease, causing a prolonged depolarisation state.
  • CDue to the high concentration of the extracellular potassium, the outflow of potassium and the resting potential will increase, causing a prolonged depolarisation state.
  • DDue to the high concentration of the extracellular potassium, the outflow of potassium and the resting potential will decrease, causing a prolonged repolarisation state.

Q8:

The graph provided shows a typical action potential in a neuron. At which part of the action potential does the neuron become inexcitable?

  • A2
  • B1
  • C5
  • D3
  • E4

Q9:

When the resting potential is being maintained, are potassium ion channels (leak channels) open or closed?

  • AClosed
  • BOpen

Q10:

After an action potential, there is a short period of time when another action potential cannot be generated. What is this period of time called?

  • ARefractory period
  • BDepolarization period
  • CInhibitory stage
  • DPause stage

This lesson includes 23 additional questions for subscribers.

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