Nerve Impulses: Transmission Flashcards

1
Q

Why do local currents occur in neurones?

A

When the sodium ions are allowed to flood into the neurone causing depolarisation, this creates local currents in the cytoplasm of the neurone.

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2
Q

Which way do the sodium ions move?

A

They move along the neurone towards regions where their concentration is still lower.

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3
Q

What do the local currents do?

A

Cause a slight depolarisation of the membrane and cause sodium ion channels further along the membrane to open (positive feedback).

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4
Q

What is saltatory conduction?

A

The action potential jumps from one node of Ranvier to the next.

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5
Q

What are the advantages of saltatory conduction?

A

Speeds up the transmission of the action potential along the neurone.

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6
Q

How does our brain determine the intensity of the stimulus? E.g. loud or quiet sounds.

A

Our brains determine the intensity of the stimulus from the frequency of action potentials arriving in the sensory region of the brain. A higher frequency of action potentials means a more intense stimulus.

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