Action Potentials

Which channels open SECOND at time #2?

• leak channels only

• gated Na channels

• gated K channels

• none

Which term best describes time #4

• polarized

• depolarization

• repolarization

• hyperpolarization

Results from opening of gated Na channels

• polarized

• depolarized

• hyperpolarized

Absolute refractory period

• 1

• 2

• 3

• 4

Relative refractory period

• 1

• 2

• 3

• 4

Why does an action potential only move forward in one direction?

• Untrue: action potentials do propagate in two directions

• Because the K+ leak channels close after having been activated

• Because the voltage-gated Na+ become inactivated for a time after first closing

• Because the axon is shaped in a linear fashion

When viewing this classic graph of an action potential, what is this really observing?

• One point in the axon over time

• The entire axon at one point in time

• The entire axon at all points in time

• Nothing during no points in time

Tags

NGSS.HS-PS3-5

During an action potential, between which two spaces are the charged particles (Na+ and K+) moved between?

• Inside the axon and inside the next (postsynaptic) cell

• Inside the axon and inside the soma (cell body)

• Inside the axon and outside the axon

• Inside the axon and inside the myelin sheath

Which statement best describes how the nervous system communicates?

• Electrical signals within one neuron; chemical signals between neurons

• Electrical signals between neurons; chemical signals within one neuron

• Electrical signals both between neurons and within each neuron

• Chemical signals both between neurons and within each neuron

If a pre-synaptic neuron fires an action potential, does that ALWAYS result in the post-synaptic neuron firing an action potential down the line in response?

• Yes

• No