Question

This was for the earthworm action potentials and I'ms just stuck on this question

in natural systems, action potentials are unidirectional. explain why you were able to measure an action potential bidirectionally

Answer 1

An action poptential is created by a threshold stimuli upon a neuron.An action potential generation is a process by which a neuron rapidly depolarises from a negative resting potential to a more positive potential,and is achieved by influx of cations(Sodium or calcium ions)through ion channels.It consists of four phases-hypopolarisation,depolarisation,overshoot and repolarisation.An action potential propagates along the cell membrane of an axon until it reaches the terminal button.

Total magnitude of an action potential is 100mV.The membrane goes from -70 to +30mV.During action potential inside of the cell becomes more positive than outside.For measuring action potential using voltmeter;a recording electrode is inserted into the cell and a referance electrode outside the cell.By comparing the charge recorded by these two electrode the transmembrane voltage is determined.Even if it is unidirectional,the charge will be the same along the entire axon and no charge is lost on conducton from presynaptic neuron to post synaptic neuron.