Action potential are the same, how can nervous system differentiate between strong and weak stimuli?
By the number of neurons firing, and the rate at which they fire. Edit: I think ATP man is going senile. He didn't ask for a description of an action potential, he asked how the brain differentiates the levels of stimuli. This is done by the number of neurons firing, and by the frequency of the action potentials. Some neurons have a low threshold, some neurons have a high threshold, and some are in the middle. Weak stimuli activate those neurons with a low threshold, stronger stimuli activate neurons with a higher threshold in addition to those with the lower threshold, and even stronger stimuli activate the ones with the highest threshold. This is the main mechanism for the differentiation of stimuli strength.
Electric potential and potential energy question?
The question is about difference between electric potential (EP) and electric potential energy (EPE). EP is usually given the symbol V (as in voltage). EP at a point means the energy that would be needed to bring 1coulomb to the point (from 'infinity'). E.g. V=10volts means it requires 10J to bring 1coulomb to the point. (1 volt is the same as a joule per coulomb.). In simple terms, EP doesn't depend on the charge you bring to the point, its the value you would get by bringing 1C. EPE depends on EP AND the amount of charge you bring to the point. E.g. V=10volts. If you bring 3C to the point (from infinity) then EPE =10x3=30J. If you bring -5C, the EPE=10x5=-50J ). Negative means the charge would be pulled to the point, losing potential energy, rather than you doing work increasing potential energy). Bearing this in mind: A) False. The EPEs must be different as the charges are different (since the EPs are the same), as in above example. B) The explanation is incorrect - it is 'back to front' V does NOT depends on the charge, EPE does. C) No. EPE and EP are not the same. D) Correct
Problem involving nervous system. An action potential is an all-or-none event...?
this on/off signaling is an evolutionary adaptation of animals that must sense and act in a complex environment. is it possible to imagine a nervous system in which the action potentials are graded, with the amplitude depending on the size of the stimulus. what advantage might on/off signaling have over a graded (continuously variable) kind of signaling?
Chemistry Lab Help on Cell Potentials?
I have these three questions on the post-lab that I just do not know how to answer. I'm not good at chemistry at all and my grade is slipping. If anyone could please help me out, it would be greatly appreciated. 1. Briefly comment on the effect of solution concentration on cell potential. Note that it is measured using 1M solutions, while your measurements were made using 0.1M. 2. A student doing this experiment using a U-tube salt bridge is having difficulty obtaining useful voltage readings. Examining the experimental setup, the student finds an air pocket between the stopper at one end of the U-tube and the electrolyte solution inside the tube. Briefly explain how the air pocket could be the source of the erroneous voltage readings. 3. If the cells you constructed in this experiment were doubled in size, would the measured cell potentials double? Briefly explain. Thank you so much if anyone can help.
Action potentials. When do the voltage gated K channels start to open?
Both Na and K channels are voltage-gated, which means when an electrical signal hits them, they activate (open or close). Thus, when a nerve impulse reaches a segment of axon with both Na and K channels, they both open at the same time. The only reason that Na flowing into the neuron doesn't completely cancel out the K flowing out of the neuron is because the K channels open much more slowly, and diffusion of positive charges outwards takes time to "catch up" with the much greater amount of positive charges flowing in. Keep in mind that the Na channels not only open faster, they also close faster, so there is a lag time for the K flow to equalize the Na flow. This could be defined as the "back end" of the nerve impulse.