Nerve Impulse Transmission- Generation Of A Nerve Impulse Flashcards

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1
Q

What is resting membrane potential?

A

The state where there is no net flow of ions across the membrane

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2
Q

What does the transmission potential require?

A

Changes in the membrane potential of the neuron’s plasma membrane

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3
Q

What is an action potential?

A

It is a wave of electrical excitation along a neuron’s plasma membrane

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4
Q

How do neurotransmitters initiate a response?

A

By binding to their receptors at a synapse

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5
Q

What are neurotransmitters receptors?

A

Ligand-binding ion channels

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6
Q

What is depolarisation of the plasma membrane a result of?

A

The entry of positive ions triggers the opening of voltage-gated sodium channels and further depolarisation occurs

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7
Q

What is depolarisation?

A

A change in the membrane potential to a less negative value inside

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8
Q

What restores the resting membrane potential?

A

The inactivation of the sodium channels and the opening of potassium channels

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9
Q

What are the steps involved in a nerve transmission?

A

The binding of a neurotransmitter triggers the opening of ligand gated ion channels at a synapse. Ion movement occurs and there is depolarisation of the plasma membrane. If sufficient ion movement occurs, and the membrane is depolarised beyond a threshold value, the opening of voltage-gated sodium channels is triggered and sodium ions enter the cell down their electrochemical gradient. This leads to a rapid and large change in the membrane potential. A short time after opening, the sodium channels become inactivated. Voltage-gated potassium channels then open to allow potassium ions to move out of the cell to restore the resting membrane potential.

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10
Q

What does depolarisation of a patch of membrane cause?

A

It causes neighbouring regions of membrane to depolarise and go through the same cycle as adjacent voltage-gated sodium channels are opened

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11
Q

What happens when the action potential reaches the end of the neuron?

A

It causes vesicles containing neurotransmitter to fuse with the membrane. This releases neurotransmitters which stimulates a response in a connecting cell

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12
Q

What does the restoration of the resting membrane potential allow?

A

It allows the inactive voltage-gated sodium channels to return to a confirmation that allows them to open again in response to depolarisation of the membrane

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13
Q

What happens following repolarisation?

A

The sodium and potassium ion concentration gradients are reduced.

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14
Q

What does the sodium-potassium pump restore?

A

the sodium and potassium ions back to resting potential levels

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15
Q

What are ion concentration gradients re-established by?

A

By the sodium-potassium pump which actively transports excess ions in and out of the cell

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