Neuro 1

In the chemical synapse the action potential causes the release of Mg²⁺ ions from vesicles into the synaptic cleft

• true

• false

The threshold voltage in an axon is usually

• Less negative than the resting membrane

• Achieved in the laboratory by applying -20 mV

• More negative than the resting membrane

• The same value as the resting membrane potential

Myasthenia gravis is a disease where the immune system attacks the myelin that covers neurons

• true

• false

If a graded receptor potential made the resting membrane potential of the axon more negative,

• It will be easier for this axon to reach the threshold voltage

• No change in the ability of this axon to reach threshold voltage

• Subsequent action potentials will be shorter in duration

• It will be more difficult for this axon to reach the threshold voltage

Voltage-gated Na+channels are the membrane channels that open

• When the membrane is at the resting membrane potential

• When the membrane hyperpolarizes

• When the membrane depolarizes

• When the membrane repolarizes

Which of the following is true of an action potential?

• The generation of an action potential uses voltage-gated Na+ channels

• An action potential is a large, all-or-none change in membrane potential

• An AP is generated when the membrane potential reaches threshold

• All of these answers are correct

The most prominent EEG wave pattern of an awake, relaxed adult whose eyes are closed is:

• delta

• alpha

• theta

• beta

When people are attentive to an external stimulus or are thinking hard about something, the alpha rhythm is replaced by

• gamma

• theta

• beta

• delta

Acetylcholinesterase is:

• Enzyme for reformation of Ach

• Excitatory neurotransmmiter necessary for muscle contraction

• Enzyme for breakdown of Ach

• Medication for myasthenia gravis

What is the role of Schwann cells in neurotransmission?

• Thermal insulation of neuronal axons

• Enhance the speed of the action potential

• Limit the speed of the action potential

• Protect the neuronal soma from trauma