Question 1

An example of a slow excitatory postsynaptic potential that involves closure of potassium channels relies on cAMP produced by what enzyme?

Accepted Answer

Adenylate cyclase is the enzyme responsible for converting ATP to cyclic AMP (cAMP) in response to a signal. In the context of a slow excitatory postsynaptic potential, the closure of potassium channels can be mediated by cAMP, which is produced by adenylate cyclase. This process typically involves a G protein-coupled receptor that activates adenylate cyclase upon stimulation.

Question 2

The most common mechanism for producing a fast EPSP involves which of the following?

Accepted Answer

Fast EPSPs are typically generated by the opening of channels that allow both sodium and potassium ions to flow, leading to depolarization.

Question 3

The final integration of postsynaptic potentials that determines whether an action potential is generated occurs within what region of a neuron?

Accepted Answer

The axon hillock is the region of a neuron where the summation of all incoming postsynaptic potentials occurs, and it determines whether the threshold is reached to generate an action potential.

Question 4

Fast excitatory responses not only occur quickly, but they

Accepted Answer

Fast excitatory responses are characterized by their quick onset and termination, meaning they end quickly rather than lasting for a long period.

Question 5

At metabotropic receptors, a(n)

Accepted Answer

Metabotropic receptors work through a process where a neurotransmitter binds to the receptor, activating a G-protein, which in turn activates a second messenger system through enzymatic actions. This is different from ionotropic receptors, where the neurotransmitter binding directly opens or closes ion channels.

Question 6

Metabotropic receptor -induced gating of ion channels requires more time to occur because of which of the following?

Accepted Answer

Metabotropic receptors act through G proteins, which then activate or inhibit downstream effectors, such as ion channels. This indirect signaling pathway takes more time compared to direct ion channel opening by ionotropic receptors.

Question 7

In the absence of active chloride ion transport, opening of chloride channels in a cell that has hyperpolarized will result in which of the following?

Accepted Answer

The answer of In the absence of active chloride ion...

Question 8

Synaptic potentials are produced at what type of synapse?

Accepted Answer

The answer of Synaptic potentials are produced at what type...

Question 9

Divergence in neurophysiology refers to which of the following?

Accepted Answer

The answer of Divergence in neurophysiology refers to which of...

Question 10

The opening of a chloride channel acts to _______axon hillock. the development of an action potential at the

Accepted Answer

The opening of a chloride channel typically results in the influx of negatively charged chloride ions into the neuron, making the inside of the neuron more negative and thus hyperpolarizing it. This hyperpolarization moves the membrane potential further away from the threshold needed to generate an action potential, thereby inhibiting the development of an action potential at the axon hillock.

Question 11

What ion directly triggers neurotransmitter release from the presynaptic neuron?

Accepted Answer

Calcium ions (Ca2+) are directly responsible for triggering neurotransmitter release from the presynaptic neuron. When an action potential reaches the axon terminal, it causes voltage-gated calcium channels to open, allowing Ca2+ to enter the neuron. This influx of calcium ions initiates the fusion of synaptic vesicles with the presynaptic membrane, leading to the release of neurotransmitters into the synaptic cleft.

Question 12

What is a change in the postsynaptic potential that brings membrane potential closer to threshold called?

Accepted Answer

An excitatory postsynaptic potential (EPSP) is a change in the postsynaptic membrane potential that makes the neuron more likely to fire an action potential. This is because the EPSP brings the membrane potential closer to the threshold needed to trigger an action potential.

Question 13

The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the_______ of _______ channels.

Accepted Answer

The binding of a neurotransmitter to its receptor at an inhibitory synapse often leads to the opening of chloride channels, which allows chloride ions to enter the neuron, making it more negative and less likely to fire an action potential.

Question 14

Convergence in neurophysiology refers to which of the following?

Accepted Answer

Convergence in neurophysiology refers to the process where multiple presynaptic neurons form synapses with a single postsynaptic neuron, allowing the integration of information from various sources.

Question 15

In the presence of active chloride ion transport within a neuron, the opening of chloride channels will result in which of the following?

Accepted Answer

The opening of chloride channels when there is active chloride ion transport typically results in a net movement of chloride into the cell, as the concentration gradient and electrochemical gradient drive chloride ions into the neuron to balance out differences in charge and concentration.

Question 16

Presynaptic modulation occurs at what type of synapse?

Accepted Answer

Axoaxonic synapses are where one neuron's axon connects to another's axon, and this configuration allows for presynaptic modulation. This type of synapse can modify the amount of neurotransmitter released from the axon terminal of the presynaptic neuron, influencing the postsynaptic neuron's response.

Question 17

In the absence of an active chloride transporter in the plasma membrane, chloride acts to_______ membrane potential by resisting any change in membrane potential.

Accepted Answer

Chloride ions help stabilize the membrane potential by resisting changes to it, acting as a buffering agent against fluctuations in membrane potential.

Question 18

If the resting membrane potential is equal to chloride's equilibrium potential, in which direction will chloride ions move if chloride channels open while the cell remains at resting membrane potential?

Accepted Answer

The answer of If the resting membrane potential is equal...

Question 19

The duration of a slow, excitatory postsynaptic potential mediated by cAMP is driven by the extent of time that cAMP remains active before being degraded by what protein?

Accepted Answer

Phosphodiesterase is responsible for degrading cAMP, thereby determining the duration of a slow, excitatory postsynaptic potential mediated by cAMP.

Question 20

The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the_______of ________ channels.

Accepted Answer

The binding of a neurotransmitter to its receptor at an inhibitory synapse often leads to the opening of potassium channels, which allows potassium ions to leave the neuron, making the inside of the neuron more negative and thus inhibiting action potential generation.

Quiz 8: Synaptic Transmission and Neural Integration