Complete the following sentences regarding excitation-contra…

Complete the following sentences regarding excitation-contraction coupling 1. When an action potential arrives at the axon terminal enters through voltage-setive channels. 2. This triggers the release of from the axon terminal. 3. This diffuses from the axon terminal to the of the skeletal muscle fiber. 4. It then binds to on the motor endplate membrane, increasing their permeability to Na+ and K+ 5. More moves into the fiber at the motor endplate than moves out, depolarizing the membrane and producing a . K

Compartments A and B are separated by a membrane that is per…

Compartments A and B are separated by a membrane that is permeable to K+K+ but not to Na+Na+ or Cl−Cl-. At time zero, a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B. Which would be true once equilibrium is reached?

During an action potential, a second stimulus, no matter how…

During an action potential, a second stimulus, no matter how strong, will not produce a second action potential because the membrane is in its   This occurs because the voltage-gated channels are either already open or have proceeded to the  state. Immediately after an action potential, some of the voltage-gated  channels that repolarized the membrane are still . During this time, a second action potential can be produced, but only if the stimulus strength is   This is the , which coincides roughly with the period of .  During this time, some of the voltage-gated Na+ channels have returned to their state, and could therefore open again.