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Flashcards in The Action Potential Deck (10)
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What does a stimulus result in?

Small patch of of membrane becoming depolarised


Give the 4 phases of the action potential?

Resting, depolarisation, polarisation and afterhyperpolarisation


What direction are action potentials propagated in?

Axon hillock to the axon terminal


A larger stimulus will produce?

A greater number of action potentials


How does the permeability for NA and K change during and action potential?

At rest NA and K closed, during depolarisation NA open, during polarisation K open while NA close, undershoot K open and NA closed


What does the all-or-nothing hypothesis state?

Unless the depolarisation reaches the threshold of -50 mv an action potential will not fire


What is the absolute refractory period?

A period where no further action potential can fire as the cell has to recover to resting state. It ensures the unidirectionality of the action potential.

A huge stimulus could cause an action potential in this period.


What does the magnitude of the action potential do at different magnitudes of stimulus?

It varies, a large stimulus equals a greater magnitude


What happens do the amplitude of an action potential as it travels away from the site of production?



What mechanisms are used to move ions across plasma membranes?

Ion pumps and ion channels