Q4.8. Which statement below is TRUE about the voltage-gated Na* channels during the action potential? The voltage-gated Na* channels are open the entire time that the neuron is depolarized (when V, is above resting potential). O The voltage-gated Na* channels open after the voltage-gated K* channels. The voltage-gated Na* channels open to restore Vm to the resting potential after the action potent peak. The voltage-gated Na channels are open when Vm is rapidly increasing during the action potenti

Question B)

A post-synaptic cell receives a signal that causes it to hyperpolarize. Which statement is NOT true about this dynamic? O The cell is now more negative than it was before. This describes an EPSP It will be harder for the cell to reach threshold and generate a new action potential. O This could have been achieved through either spatial or temporal summation.

At a chemical synapse, what happens? O action potentials are propagated more quickly than at an electrical synapse O the postsynaptic neuron converts an electrical signal into a chemical signal O the presynaptic neuron converts an electrical signal into a chemical signal O two cells communicate directly via connections at gap junction O there is a synaptic delay of about 3 seconds as the neurotransmitter crosses the synaptic cleft < Previous

Membrane Potential (mV) The Action Potential 1. Label the significant membrane potentials and phases of the action potential in a neuron. Indicate which gates are open/closed as well as the direction of the net movement of sodium and potassium ions across the cell membrane for A-G. +30- 0 -55-B -70- -80- 0 H [T E 2 F 3 Time (ms) G 4 5

Q5.3. After the rising phase, which ion channel is responsible for action potential returning to its resting Vm, and why? Na+ channels, because positive Na* ions are at higher concentration outside the axon than inside, and so they enter the axon and raise V m Na* channels, because positive Na* ions are at higher concentration inside the axon than outside, and so they leave the axon and raise Im K* channels, because positive K* ions are at higher concentration outside the axon than inside, and so they enter the axon and raise Vm K+ channels, because positive K* ions are at higher concentration inside the axon than outside, and so they leave the axon and lower Vm Submit