Flashcards in The Action Potential Deck (10)
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?