Question 1

Marcus is excited to be working in the laboratory of Dr.Flores,an expert on electrical signaling in neurons.However,he is surprised to learn that the research is done on squid axons placed in sea water.He asks Dr.Flores the reasons for this.Which of the following is NOT one of the reasons that Dr.Flores provides?

Accepted Answer

Squid axons are actually unmyelinated, meaning they do not have the protective covering that increases the speed of action potential propagation seen in vertebrate axons. Therefore, this would not be a reason for using squid axons in Dr. Flores' research. The other options are all valid reasons for using squid axons in this type of research.

Question 2

The arrival of a(n)____ causes synaptic vesicles to be released from their protein anchors,allowing the vesicles to fuse with the cell membrane and release ____ into the synaptic cleft.

Accepted Answer

An action potential is an electrical impulse that travels down the axon of a neuron, causing synaptic vesicles to be released from their protein anchors. These vesicles then fuse with the cell membrane and release neurotransmitters into the synaptic cleft, the small gap between the sending neuron and the receiving neuron. Therefore, choice A is the correct answer. Choice B is incorrect because neurotransmitters themselves do not cause an electrical charge. Choice C is partially correct because an action potential does involve an electrical charge, but it is the action potential that causes the vesicles to release neurotransmitters, not an electrical charge being directly released. Choice D is incorrect because releasing more neurotransmitters would require additional action potentials to be generated, but it does not directly answer the question of what causes the release of neurotransmitters in the first place.

Question 3

Juan,a graduate student in an electrophysiology lab,stimulates an isolated neuron grown in a petri dish and measures its action potential.How will the neuron respond to the firing of the action potential?

Accepted Answer

When a neuron fires an action potential, it typically leads to the release of chemical messengers, or neurotransmitters, from the axon terminals into the synaptic cleft.

Question 4

Elaine,a graduate student in a neuroscience department,is interested in understanding the effects of popular herbal remedies on neuronal communication.After growing neurons in a petri dish,she exposes the neurons to several common herbal supplements.After performing a series of electrophysiology experiments,she notes that one class of herbal supplements caused the neurons to become depolarized.What does this mean?

Accepted Answer

Depolarization means the inside of the neuron becomes less negative compared to the outside, decreasing the charge difference and increasing the likelihood of an action potential.

Question 5

Once the "threshold" for an action potential is reached what is the sequence of events that occur?
1)Potassium channels are activated and potassium ions move out of the neuron.
2)Sodium channels are activated and sodium ions move into the neuron.
3)The interior of the neuron becomes more negatively charged than the exterior.
4)The interior of the neuron becomes more positively charged than the exterior.

Accepted Answer

Once the threshold for an action potential is reached, sodium channels are activated and sodium ions move into the neuron, causing the interior of the neuron to become more positively charged than the exterior. This depolarization triggers the activation of potassium channels, causing potassium ions to move out of the neuron and the interior of the neuron to become more negatively charged than the exterior. Therefore, the correct sequence of events is 2, 4, 1, and 3. Choice B matches this sequence.

Question 6

Following a spinal cord injury,formation of the ____ prevents neuronal regeneration in the ____.

Accepted Answer

After a spinal cord injury, scar tissue formed by glia prevents neuronal regeneration in the central nervous system. The blood-brain barrier is not directly involved in this process, and while scar tissue can also form in the peripheral nervous system after injury, it is typically not as inhibitory to regeneration.

Question 7

Synaptic vesicles have been released from their protein anchors.What happens next?

Accepted Answer

After synaptic vesicles are released from their protein anchors, they migrate to the cell membrane, release neurotransmitters into the synaptic gap, and are then often refilled for reuse.

Question 8

Marcus works in the laboratory of Dr.Flores,an expert in the electrophysiology of squid axons.After taking a reading from a recording electrode placed within a squid axon,Marcus comments to Dr.Flores that the squid axon is at its resting potential.What measurement did Marcus take with the recording electrode?

Accepted Answer

The resting potential of a squid axon is typically around -70 mV. Therefore, Marcus must have recorded a voltage of -70 mV with the recording electrode.

Question 9

Marcus is conducting a squid axon electrophysiology experiment with Dr.Flores.While monitoring a recording electrode placed within a squid axon,Marcus reports to Dr.Flores that the neuron is in a refractory period.What does this mean?

Accepted Answer

During the refractory period, the neuron is temporarily unable to produce another action potential. In the absolute refractory period, the neuron is incapable of producing another action potential, regardless of the stimulus. This occurs when the voltage-gated sodium channels are inactivated and cannot be opened. In the relative refractory period, the neuron requires a stronger than normal stimulus to produce another action potential. This occurs when the membrane potential is hyperpolarized, making it more difficult for the voltage-gated sodium channels to open. Therefore, choice A is the best answer as it describes the hyperpolarization of the cell during the refractory period.

Question 10

Marcus,who works in the laboratory of Dr.Flores,a prominent electrophysiologist,takes readings with a recording electrode placed within a squid axon.He reports to Dr.Flores that the cell is firing an action potential.What measurement did Marcus take with the recording electrode?

Accepted Answer

A squid axon has a resting membrane potential of around -70mV, which means that it is negatively charged inside compared to the outside. However, when an action potential fires, the charge inside the axon rapidly becomes positive, reaching a peak of around +40mV before returning to its resting potential. Therefore, the measurement Marcus took with the recording electrode when the cell was firing an action potential would be around +40mV, corresponding to the peak of the positive charge inside the axon during the action potential.

Question 11

Chemical messengers used in neuronal communication are referred to as ____.

Accepted Answer

The term used to describe chemical messengers used in neuronal communication is neurotransmitters. A, B, and C are not commonly used terms to describe this concept in neuroscience.

Question 12

A squid axon is large enough to be visible to the naked eye,while a human axon can only be viewed with a microscopic.Compared with an action potential for a human axon,the size of an action potential for a squid axon will be ____.

Accepted Answer

The size of an action potential is determined by the properties of the axonal membrane and ion channels, not the size of the axon itself. Therefore, the action potential size is the same for both squid and human axons.

Question 13

Myelin,which insulates many neuronal axons,is formed by ____.

Accepted Answer

Myelin is formed by the glial membranes, specifically the Schwann cells in the peripheral nervous system and the oligodendrocytes in the central nervous system. These glial cells wrap around the axons and form the myelin sheath, which enables faster and more efficient nerve impulse transmission.

Question 14

Neuronal communication is a two-step process.In the second step,which takes place between two neurons,what does the arrival of an action potential at the axon terminal of the first neuron signal?

Accepted Answer

The arrival of an action potential at the axon terminal of the first neuron signals the release of neurotransmitters into the extracellular fluid, which then binds to receptors on the second neuron, initiating the process of neuronal communication. Option A is incorrect because the synthesis of neurotransmitters occurs in the cell body of the neuron, not in the axon terminal. Option B is incorrect because neurotransmitters are released from the axon terminal, not taken up from the extracellular space. Option C is incorrect because enzymatic breakdown of residual neurotransmitters occurs in the extracellular fluid, which does not involve the arrival of an action potential at the axon terminal.

Question 15

Georgio is jogging barefoot along the beach when he suddenly steps on the sharp edge of a broken shell.He instantly feels pain due to the message carried to his brain by ____.He then slowly walks home with an achy foot.The message of the ache is carried by ____.

Accepted Answer

Myelinated axons are responsible for transmitting fast, sharp pain signals, while unmyelinated axons transmit slower, aching pain signals.

Question 16

Which is an accurate statement regarding the generation of an action potential?

Accepted Answer

An action potential is generated when a neuron becomes depolarized to the threshold level. The threshold level is usually around -55mV. Hyperpolarization is when the neuron becomes more negative, while depolarization is when the neuron becomes more positive. Small or large hyperpolarizations do not result in action potentials - it is the depolarization to the threshold level that triggers an action potential. Similarly, the size of the action potential is not determined by the size of the depolarization, but rather by the all-or-nothing nature of the action potential.

Question 17

Professor Freeman calls on his student Maya to describe how the presence of myelin affects an action potential.Maya should respond with which of the following statements?

Accepted Answer

The answer of Professor Freeman calls on his student Maya...

Question 18

How does myelination affect the signal transmission of a neuron?

Accepted Answer

Myelination speeds up the transmission of a signal by allowing the signal to jump from one node of Ranvier to the next, rather than traveling down the entire axon. This process is known as saltatory conduction and allows for faster and more efficient signal transmission.

Question 19

Denise,a first-year graduate student,is getting ready to begin a lab rotation with Dr.Hudson,an expert on the nodes of Ranvier.What should Denise know about the nodes of Ranvier before beginning her lab rotation?

Accepted Answer

Action potentials occur only at the nodes of Ranvier in myelinated axons because the myelin sheath insulates the axon and prevents the action potential from propagating along the axon. The action potential can only jump from one node of Ranvier to the next, which is why myelinated axons conduct action potentials much faster than unmyelinated axons.

Question 20

Synaptic communication between two neurons usually occurs via ____.

Accepted Answer

Synaptic communication between two neurons usually occurs via chemical messengers called neurotransmitters, which are released by the presynaptic neuron and bind to receptors on the post-synaptic neuron.

Quiz 4: The Biological Mind the Physical Basis of Behavior

The arrival of a(n) causes synaptic vesicles to be released from their protein anchors,allowing the vesicles to fuse with the cell membrane and release into the synaptic cleft.

Juan,a graduate student in an electrophysiology lab,stimulates an isolated neuron grown in a petri dish and measures its action potential.How will the neuron respond to the firing of the action potential?

Following a spinal cord injury,formation of the prevents neuronal regeneration in the .

Synaptic vesicles have been released from their protein anchors.What happens next?

Marcus is conducting a squid axon electrophysiology experiment with Dr.Flores.While monitoring a recording electrode placed within a squid axon,Marcus reports to Dr.Flores that the neuron is in a refractory period.What does this mean?

Marcus,who works in the laboratory of Dr.Flores,a prominent electrophysiologist,takes readings with a recording electrode placed within a squid axon.He reports to Dr.Flores that the cell is firing an action potential.What measurement did Marcus take with the recording electrode?

Chemical messengers used in neuronal communication are referred to as ____.

A squid axon is large enough to be visible to the naked eye,while a human axon can only be viewed with a microscopic.Compared with an action potential for a human axon,the size of an action potential for a squid axon will be ____.

Myelin,which insulates many neuronal axons,is formed by ____.

Neuronal communication is a two-step process.In the second step,which takes place between two neurons,what does the arrival of an action potential at the axon terminal of the first neuron signal?

Georgio is jogging barefoot along the beach when he suddenly steps on the sharp edge of a broken shell.He instantly feels pain due to the message carried to his brain by .He then slowly walks home with an achy foot.The message of the ache is carried by .

Which is an accurate statement regarding the generation of an action potential?

Professor Freeman calls on his student Maya to describe how the presence of myelin affects an action potential.Maya should respond with which of the following statements?

How does myelination affect the signal transmission of a neuron?

Denise,a first-year graduate student,is getting ready to begin a lab rotation with Dr.Hudson,an expert on the nodes of Ranvier.What should Denise know about the nodes of Ranvier before beginning her lab rotation?

Synaptic communication between two neurons usually occurs via ____.

Quiz 4: The Biological Mind the Physical Basis of Behavior

The arrival of a(n) ____ causes synaptic vesicles to be released from their protein anchors,allowing the vesicles to fuse with the cell membrane and release ____ into the synaptic cleft.

Juan,a graduate student in an electrophysiology lab,stimulates an isolated neuron grown in a petri dish and measures its action potential.How will the neuron respond to the firing of the action potential?

Following a spinal cord injury,formation of the ____ prevents neuronal regeneration in the ____.

Synaptic vesicles have been released from their protein anchors.What happens next?

Marcus is conducting a squid axon electrophysiology experiment with Dr.Flores.While monitoring a recording electrode placed within a squid axon,Marcus reports to Dr.Flores that the neuron is in a refractory period.What does this mean?

Marcus,who works in the laboratory of Dr.Flores,a prominent electrophysiologist,takes readings with a recording electrode placed within a squid axon.He reports to Dr.Flores that the cell is firing an action potential.What measurement did Marcus take with the recording electrode?

Chemical messengers used in neuronal communication are referred to as ____.

A squid axon is large enough to be visible to the naked eye,while a human axon can only be viewed with a microscopic.Compared with an action potential for a human axon,the size of an action potential for a squid axon will be ____.

Myelin,which insulates many neuronal axons,is formed by ____.

Neuronal communication is a two-step process.In the second step,which takes place between two neurons,what does the arrival of an action potential at the axon terminal of the first neuron signal?

Georgio is jogging barefoot along the beach when he suddenly steps on the sharp edge of a broken shell.He instantly feels pain due to the message carried to his brain by ____.He then slowly walks home with an achy foot.The message of the ache is carried by ____.

Which is an accurate statement regarding the generation of an action potential?

Professor Freeman calls on his student Maya to describe how the presence of myelin affects an action potential.Maya should respond with which of the following statements?

How does myelination affect the signal transmission of a neuron?

Denise,a first-year graduate student,is getting ready to begin a lab rotation with Dr.Hudson,an expert on the nodes of Ranvier.What should Denise know about the nodes of Ranvier before beginning her lab rotation?

Synaptic communication between two neurons usually occurs via ____.

The arrival of a(n) causes synaptic vesicles to be released from their protein anchors,allowing the vesicles to fuse with the cell membrane and release into the synaptic cleft.

Following a spinal cord injury,formation of the prevents neuronal regeneration in the .

Georgio is jogging barefoot along the beach when he suddenly steps on the sharp edge of a broken shell.He instantly feels pain due to the message carried to his brain by .He then slowly walks home with an achy foot.The message of the ache is carried by .