When a neuron is depolarized, what are the first channels to open?

• Calcium

• Potassium

• Sodium

• ACTH

When a neuron is not engaged in the transmission of an impulse.

• Synaptic potential

• Action potential

• Neural potential

• Resting potential

Why is -55 mV a significant number?

• This is the largest charge achieved during an action potential

• This is the charge when all the sodium is inside the cell

• This is the resting charge of a neuron

• This is the threshold required to complete an action potential

Why is the speed of an impulse increased if a neuron is wrapped in myelin?

• potassium ions flow out of the neuron faster

• myelin insulates the neuron so the temperature increases

• the impulse can jump from node to node

• it allows neurons to touch each other

In the figure above, what is occurring at step #4?

• K⁺ channels open allowing K⁺ to diffuse out, repolarizing the membrane

• Na⁺ channels open allowing Na⁺ to diffuse inward, depolarizing the membrane

• K⁺ channels open and Na⁺ channels open, action potential begins

• Neuron receives enough stimulation, threshold is reached

• Na⁺ are being pumped out and K⁺ are being pumped into the cell

The space between a presynaptic and post synaptic neuron

• Synaptic cleft

• Dendrite gap

• Nodes of Ranvier

• Neuromuscular junction

When a membrane potential reaches +30mV, ________ channels open, ________ occurs, and ________ channels close.

• Sodium, depolarization, potassium

• Potassium, repolarization, sodium

• Sodium, repolarization, potassium

• Potassium, depolarization, sodium

Multiple sclerosis is an autoimmune disease in which the body's own immune system destroys the _____________ of the nerve axons.

• Nodes of Ranvier

• Dendrites

• Axon Terminal

• Myelin sheath

What chemical is activated by the action potential in the presynaptic neuron that causes the vesicles containing neurotranmitters to move toward the synaptic cleft?

• Potassium

• Sodium

• Calcium

• Phosphorus

What's in the picture?

• Synaptic cleft

• Neurotransmitters

• Presynaptic neuron

• Postsynaptic neuron

• Synaptic vesicles