Action Potentials Flashcards

1
Q

How many signals can a neuron send at once?

A

1

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2
Q

A neuron can only transmit at a uniform…

A

-Strength
-Speed

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3
Q

What can a neuron vary?

A

The frequency of the signals

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4
Q

What is voltage?

A

Measure of potential energy generated from separated charges

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5
Q

What is another word for voltage?

A

Membrane potential

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6
Q

What is another word for membrane potential?

A

Voltage

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7
Q

What is current?

A

Flow of charge from one point to another

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8
Q

What is the equation for current?

A

Current = Voltage/Resistance

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9
Q

What is resistance?

A

Whatever is getting in the way of the current

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10
Q

Where is a resting neuron more negative?

Inside or Outside

A

On the inside

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11
Q

Where is a resting neuron more positive?

Inside or Outside

A

On the outside

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12
Q

What is the resting membrane potential?

A

-70mV
Polarised

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13
Q

What is the net movement of ions through the sodium-potassium pump?

A

2K+ in and 3Na+ out

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14
Q

What maintains resting membrane potential?

A

The sodium-potassium pump

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15
Q

What does the sodium-potassium pump help achieve?

A

Makes it more positive on the outside

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16
Q

What is another word for the difference in membrane potentials?

A

Electrochemical gradient

17
Q

What are voltage-gated channels?

A

They open and close in response to changes in membrane potential

18
Q

At what voltage do Na⁺ voltage-gated channels open?

19
Q

What are ligand-gated channels?

A

They open when neurotransmitters latch to their receptors

20
Q

What is an example of a ligand-gated channel?

21
Q

What are mechanically-gated channels?

A

-They open in response to physical stretching of the membrane
-Ions quickly diffuse down concentration gradient

22
Q

What is the propagation of an action potential?

A

Action potentials spreading over the surface of an axon membrane

23
Q

How is an action potential propagated over the surface of the axon?

A

-As Na⁺ flows into the cell during depolarisation, the voltage of adjacent areas is affected and their voltage-gated Na⁺ channels open
-Self-propagating along membrane

24
Q

What is another phrase for a travelling action potential?

A

Nerve impulse

25
What is another name for a nerve impulse?
Travelling Action Potential
26
What is continuous conduction?
-Unmyelinated fibres -Step-by-step depolarisation of each portion of the length of the axolemma
27
Where does repolarisation occur?
Nodes of Ranvier
28
Why can repolarisation only occur at nodes of ranvier?
There is a high density of voltage-gated ion channels
29
What is saltatory conduction?
Current carried by ions flows through extracellular fluid from node to node
30
Where does saltatory conduction take place?
Myelinated axons