Please answer these questions and please explain in details. 1- If you increase
ID: 55261 • Letter: P
Question
Please answer these questions and please explain in details.
1- If you increase the extracellular concentration of Na+ ions, what effect would this have on the various steps of an action potential?
2- If you increase the extracellular concentration of K+ ions, what effect would this have on the various steps of an action potential?
3- Which of the following changes (or effects of drugs/poison/venom) at the synapse would decrease/increase the magnitude of graded potentials generated on the on the post synaptic cell?
Explanation / Answer
1. If there is an increase in the extracellular concentration of Na+ ions, There is an increase in the membrane potential of the nerve cell. If the concentration of Na+ ions are increased the action potential is larger and if it is decreased the action potential becomes smaller. The relation ship can be expressed with Nersten equation.
2. If the extracellular concentration of K+ ions increase, the membrane potential of the cell will not reach the ideal value, because it is controlled by Na+ diffusion. The equilibrium is controlled in one extreme border as -75mv in the K+ ion diffusion and +55mV in the presence of Na+ ion diffusion. This is explained by GHK equaion.
3. The venom will decrease the magnitude of graded potentials generated on the post synaptic cell by inhibiting the ion channels which alters the membrane potential.