Nerve Impulses: Transmission Flashcards
Why do local currents occur in neurones?
When the sodium ions are allowed to flood into the neurone causing depolarisation, this creates local currents in the cytoplasm of the neurone.
Which way do the sodium ions move?
They move along the neurone towards regions where their concentration is still lower.
What do the local currents do?
Cause a slight depolarisation of the membrane and cause sodium ion channels further along the membrane to open (positive feedback).
What is saltatory conduction?
The action potential jumps from one node of Ranvier to the next.
What are the advantages of saltatory conduction?
Speeds up the transmission of the action potential along the neurone.
How does our brain determine the intensity of the stimulus? E.g. loud or quiet sounds.
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.
