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Bio 109 Quiz 6

Terms in this set (17)

A change in the membrane potential of a neuron from a value of -70 mV to a value of -60 mV would be called:
Depolarization
Which of the following statements concerning the propagation of action potential is incorrect?
Strong stimuli generate stronger action potentials than weaker stimuli.
In a neuron, resting potential is maintained by maintaining a gradient of:
Potassium and Sodium ions
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?
Voltage-gated calcium channels in the membrane open.
Assume that a single IPSP has a negative magnitude of -0.5 mV at the axon hillock, and that a single EPSP has a positive magnitude of +0.5 mV. For a neuron with an initial membrane potential of -70 mV, the net effect of the simultaneous arrival of 2 IPSPs and 6 EPSPs would be to move the membrane potential to
-68 mV
The following steps refer to various stages in transmission at a chemical synapse.
1. Neurotransmitter binds with receptors associated with the postsynaptic membrane.
2. Calcium ions rush into neuron's cytoplasm.
3. An action potential depolarizes the membrane of the presynaptic axon terminal.
4. The ligand-gated ion channels open on the post synaptic membrane.
5. The synaptic vesicles release neurotransmitter into the synaptic cleft.
Which sequence of events is correct?
3 → 2 → 5 → 1 → 4
In a resting potential, an example of a cation that is more abundant in the cytosol of a neuron than in the interstitial fluid outside the neuron is:
K+
The transmission of an action potential typically requires the cell membrane to reach threshold in which region?
axon hillock
Action potentials move along axons:
more rapidly in myelinated than in non-myelinated axons.
A change in the membrane potential of a neuron from a value of -70 mV to a value of -80 mV would be called:
hyperpolarization
The point of connection between two communicating neurons is called the:
synapse
Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it. The sodium channel is a:
ligand-gated sodium channel.
The adding together of EPSPs generated by a single presynaptic terminus is an example of:
temporal summation
In a simple synapse, neurotransmitter chemicals are released by:
the presynaptic membrane
When two excitatory postsynaptic potentials (EPSPs) occur at a single synapse so rapidly in succession that the postsynaptic neuron's membrane potential has not returned to the resting potential before the second EPSP arrives, the EPSPs add together, producing:
temporal summation
The diagram above shows two neurons (i and ii). The letter C points to dendrites while the letter B points to axon hillock .
C: dendrites
B: axon hillcock
Threshold stimuli are stimuli that are strong enough to:
cause a net flux of positively charged ions from inside to outside the cell.
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