The one-way propagation of action potentials away from the original site of activation is ensured by the

13) Draw a graph representing the changes in membrane potential across the axonal membrane before, during, and after an action potential. On your graph, use a highlighter to clearly indicate for which portions of your graph the letter corresponding to each cellular event listed below belongs. List of cellular events: A) All K* channels open B) All Na* channels close C) The Na*/K* ATPase cotransporter transports Na* and K* across the membrane. D) All Na* channels open E) The threshold value of membrane potential is attained. F) All K* channels close G) Some Na* channels open Your graph:

True or false: Manipulating the synthesis of neurochemicals produces only short-term effects in most cases due to sensitive feedback loops for neurochemical production.

What would be the effect of increased (or decreased)concentration of extracellular Ca2+ on the function of thepresynaptic cell? How would you assess this effect experimentally?