okay this vid we're gonna talk about graded potentials now creative potentials are short-lived localized changes in membrane potential or voltage so we find here is that the stronger the stimulus the more voltage change that occurs and the farther that current flows now these graded potentials think about them as almost like a wave of voltage and these waves are ultimately triggered by a stimulus that opens gated ion channels now this results in depolarization sometimes hyperpolarization as well and they're named for the location so we talked about the EM plate potential back in the neuromuscular Junction which is the type of graded potential that occurs at the motor in plate now receptor potential is actually also called generator potential this is actually where graded potentials and receptors of sensory neurons are formed and so when you maybe smell an odorant molecule that creates a receptor potential which may or may not trigger an action potential now postsynaptic potential is a neuron grid potential and these occur within the dendrites of neurons the cell bodies of neurons and this may or may not cause an action potential to be formed so if you think about what this great potential is it's basically a local area of membrane potential change we're saying that in this example there's a stimulus that causes a local area of depolarization and this depolarization can spread and as it spreads that local area of depolarization also dissipates and gets smaller and smaller and smaller so in a lot of ways it's like it's like a wave in a pond where once the wave is formed it gets smaller over time and distance now we find that graded potentials are caused by these gated ion channels opening and depolarization or hyperpolarization can spread from one area of the membrane to the next and so as the depolarization spreads you find that there's little local areas of positive charge however it also gets smaller as it spreads so as you see over here as its depolarization wave spreads and it dissipates the effect on voltage locally becomes less so you can see that at this point where the receptor potential was generated you know you see that this there's a strongest change of voltage that which is illustrated by this darker red color and as these positive charges spread inside of the axon or just somewhere in the cell you know they become more or less concentrated and by being less concentrated you see that that the change of voltage is actually less than it would be at the point of generation so current flows but dissipates quickly and also decays so greater potentials or signals but only over very short distances and over time the current dissipates so much that the local area of voltage also decreases so what we find that is that this might be the point of initial depolarization and you might be really depolarized at this point but as this current spreads inside the cell it gets closer and closer and closer back towards resting membrane potential because the ions dissipate and then their effect on the the resting voltage becomes less and less