Nerve Impulses Flashcards

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1
Q

The resting potential

A

The inside of the neutron is more negative relative to the outside. The difference is maintained primarily by sodium-potassium pumps (Active membrane transport)

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2
Q

Action potentials

A

Are the rapid localised change in membrane charge that occurs in order to generate and propagate an electrical impulse along the neutron

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3
Q

Three main stages of action potentials

A
  1. Depolarisation
  2. Repolarisation
  3. Refractory period
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4
Q

How does depolarisation occur?

A

As a stimulus reaches the membrane, sodium channels allow Na+ to flow in, depolarising the membrane and making it less negative

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5
Q

What happens during the refractory period and why does refractory period occur?

A

At this stage, the resting ionic distribution is largely reversed. The resting potential must be restored by the sodium-potassium pump. The nerve can’t fire again until the resting potential is restored.

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6
Q

Repolarisation

A

The sodium channels then close and potassium channels open, allowing K+ ions to escape which causes the membrane potential to return to a more negative internal differential

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7
Q

Propagation of the action potential

A
  1. Nerve impulses are action potentials that move along the length of an axon as a wave of depolarisation
  2. The ion channels that occupy the length of the axon are voltage-gated
  3. Depolarisation at one point of the axon triggers the opening of the ion channels in the next segment of the axon
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8
Q

Oscilloscopes

A

Oscilloscopes measure and show the membrane potential changes at rest and during an action potential.

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9
Q

Myelin

A

Some neutrons are covered in a fatty, white, insulating substance called myelin. This layer increases the speed of nerve impulse in transmission by saltatory conduction

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10
Q

Myelination

A

In myelinated neurons, the action potentials’ a hop between the gaps in the myelin sheath called the nodes of ranvier

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