Neurons & Messages

1. 1When the Neurons membrane is at rest where are the sodium ions and potassium ions most concentrated?

   1. ASodium is mostly outside and potassium is mostly inside
   2. BSodium is mostly inside and potassium is mostly outside
   3. CBoth ions are mostly inside
   4. DBoth ions are mostly outside the cell
2. 2When the membrane is at rest what are the forces acting on sodium ions?

   1. ABoth the concentration gradient and the electrical gradient tend to move sodium ions into the cell
   2. BConcentration and electrical tend to move sodium out of the cell
   3. CConcentration and electrical tend to move sodium into cell & electrical moves them out
   4. DConcentration moves sodium out and electrical moves them out
3. 3When the membrane is at rest what are the forces acting on potassium ions?

   1. ABoth concentration and electrical gradients move potassium into the cell
   2. BBoth concentration and electrical gradients move potassium out of the cell
   3. CThe concentration gradient tends to move potassium ions into the cell, and the electrical gradient tends to move them out of the cell.
   4. DThe concentration gradient tends to move potassium ions out of the cell, and the electrical gradient tends to move them into the cell.
4. 4Which direction does the sodium-potassium pump move ions?

   1. AIt moves both sodium & potassium ions into the cell
   2. BIt moves both sodium & potassium ions out of the cell
   3. CMoves sodium ions into the cell & potassium ions out of the cell
   4. DMoves sodium ions out of the cell & potassium ions into the cell
5. 5Under what conditions does an axon produce an action potential?

   1. AWhenever the membrane is hyperpolarized
   2. BMembrane potential reaches threshold
   3. CWhen membrane is depolarized
   4. DWhen membrane potential reaches zero
6. 6If a membrane is depolarized to twice its threshold what happens?

   1. ANeuron produces an action potential at twice the strength as usual
   2. BNeuron produces action potential that travels twice as fast as usual
   3. CThe neuron produces action potential slightly stronger & faster than usual
   4. DNeuron produces same action potential it would at threshold
7. 7To which part or parts of a neuron does the all or none law apply?

   1. AAxons
   2. BDendrites
   3. CBoth axons & dendrites
   4. DNeither axons or dendrites
8. 8During the rising potential which ions are moving across the membrane and in which direction?

   1. ASodium ions move out
   2. BSodium ions move in
   3. CBoth sodium & potassium ions move in
   4. DPotassium ions move in
9. 9After action potential reaches its peak the potential across the membrane falls towards its resting level. What accounts for this recovery?

   1. AThe sodium-potassium pump removes extra sodium
   2. BSodium ions move out because their channels are open & concentration gradient pushes them out
   3. CPotassium ions move out because their channels are open-concentration gradient pushes them out
   4. DPotassium ions move in
10. 10What does the myelin sheath of an axon accomplish?

    1. AEnables an axon to communicate with other axons
    2. BEnables action potentials to travel both in directions along an axon
    3. CEnables nutrients to enter axon
    4. DEnables action potential to travel faster

11. 11What causes the refractory period of an axon?

    1. AThe sodium–potassium pump becomes inactive.
    2. BThe sodium–potassium pump increases its activity.
    3. CPotassium channels are closed
    4. DSodium channels are closed

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Quiz on Neurons & Messages, created by Steve Hood on 25/10/2020.

Author

Steve Hood

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English

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