Question 1

Synaptic vesicles store

Accepted Answer

Synaptic vesicles are specialized organelles within neurons that store neurotransmitters, which are chemicals used by neurons to communicate with each other at synapses.

Question 2

What type of synapse occurs between an axon terminal of one neuron and the axon from another neuron?

Accepted Answer

Axoaxonic synapses occur between the axon terminal of one neuron and the axon of another neuron.

Question 3

For cells that communicate by electrical synapses, the message travels between cells via

Accepted Answer

Electrical synapses communicate through gap junctions, which allow direct cytoplasmic connections between cells for ions and small molecules to pass rapidly, facilitating quick signal transmission.

Question 4

What type of synapse occurs between an axon terminal of one neuron and the cell body of another neuron?

Accepted Answer

Axosomatic synapses occur between the axon terminal of one neuron and the soma (cell body) of another neuron.

Question 5

The influx of calcium into the axon terminal of a chemical synapse is responsible for which of the following?

Accepted Answer

The influx of calcium into the axon terminal triggers the fusion of synaptic vesicles with the presynaptic membrane, leading to the release of neurotransmitters into the synaptic cleft through exocytosis.

Question 6

The neurotransmitter that is released from the presynaptic neuron must diffuse across the_______ to reach the postsynaptic neuron.

Accepted Answer

The neurotransmitter released from the presynaptic neuron must diffuse across the synaptic cleft to reach and bind to receptors on the postsynaptic neuron, facilitating communication between neurons.

Question 7

What type of receptor is responsible for the rapid opening of ion channels in response to the interaction between the ligand and receptor?

Accepted Answer

Ionotropic receptors are responsible for the rapid opening of ion channels upon ligand binding, allowing ions to flow across the membrane and alter the cell's electrical potential.

Question 8

Which of the following statements about synapses is FALSE?

Accepted Answer

Neurotransmitters do not move through gap junctions at electrical synapses. Instead, electrical synapses allow ions to pass directly between cells, facilitating rapid communication. Neurotransmitters are involved in chemical synapses, where they are released from one neuron and bind to receptors on another neuron across a synaptic cleft.

Question 9

The chemical synapse is bounded by the_______neuron, from which neurotransmitters are released across the synaptic cleft, to the_______neuron, where the receptors for that neurotransmitter are located.

Accepted Answer

The chemical synapse consists of a presynaptic neuron, which releases neurotransmitters, and a postsynaptic neuron, where the neurotransmitter receptors are located.

Question 10

The rapid change in membrane potential that occurs when a ligand binds to an ionotropic receptor is caused by which of the following?

Accepted Answer

Ionotropic receptors function as both receptors and ion channels, allowing for the rapid change in membrane potential when a ligand binds to them. This direct gating of the ion channel by the ligand (without the involvement of G proteins) leads to immediate changes in ion flow across the membrane.

Question 11

Neurotransmitter release occurs by what mechanism?

Accepted Answer

Neurotransmitter release occurs by exocytosis, where vesicles containing neurotransmitters fuse with the presynaptic membrane and release their contents into the synaptic cleft.

Question 12

Voltage -gated calcium channels in the axon terminal open in response to which of the following?

Accepted Answer

Voltage-gated calcium channels in the axon terminal open in response to the arrival of an action potential at the axon terminal. This influx of calcium ions triggers the release of neurotransmitters into the synaptic cleft.

Question 13

Which of the following statements about electrical synapses is FALSE?

Accepted Answer

Electrical synapses, characterized by gap junctions, allow for direct current flow between cells, facilitating rapid, synchronized firing of neurons. They are not limited to small-response, single neuron firing but are involved in coordinated activity across neuron populations.

Question 14

Most neurotransmitters are synthesized in what region of a neuron?

Accepted Answer

Neurotransmitters are primarily synthesized in the cytosol of the axon terminal, where they are then packaged into synaptic vesicles for release during synaptic transmission.

Question 15

Neurotransmitters can be reused through the process of _______, where neurotransmitters are transported back across the presynaptic membrane.

Accepted Answer

Reuptake is the process by which neurotransmitters are taken back into the presynaptic neuron after being released into the synaptic cleft. This allows the neurotransmitters to be reused in subsequent communications between neurons.

Question 16

Which of the following is NOT a mechanism whereby neurotransmitters are rapidly removed from the synaptic cleft?

Accepted Answer

Neurotransmitters are not transported back up the axon to be immediately repackaged; instead, they are typically removed by reuptake, enzymatic degradation, or diffusion.

Question 17

The synaptic delay is caused by the time required for which step of neurotransmitter release?

Accepted Answer

The answer of The synaptic delay is caused by the...

Question 18

The action of any chemical messenger ultimately depends not on the nature of the messenger, but rather on the

Accepted Answer

The action of a chemical messenger is determined by the signal transduction mechanism it activates, which dictates the cellular response.

Question 19

The extent of neurotransmitter binding to receptors on the postsynaptic membrane is determined primarily by which of the following?

Accepted Answer

The concentration of neurotransmitter in the synaptic cleft primarily determines how much neurotransmitter can bind to receptors on the postsynaptic membrane. Higher concentrations increase the likelihood of neurotransmitter molecules binding to receptors, influencing the strength of the signal transmitted.

Question 20

What type of ion channels is necessary for the function of the axon and the axon terminal?

Accepted Answer

Voltage-gated ion channels are essential for the function of the axon and the axon terminal, as they are responsible for the propagation of action potentials along the axon and the release of neurotransmitters at the axon terminal.

Quiz 8: Synaptic Transmission and Neural Integration