Nervous System - High School Biology
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How does the sodium-potassium pump establish a resting potential in neurons?
How does the sodium-potassium pump establish a resting potential in neurons?
The sodium potassium-pump is used in order to establish the negative resting potential in neurons. Since both sodium and potassium ions are positively charged, there needs to be more ions leaving the cell compared to ions entering. The pump accomplishes this by pumping three sodium ions out of the cell, while pumping two potassium ions into the cell. This loss of positive charge inside the cell results in the negative resting potential of neurons.
Thank about the net transfer of ions. Three positive sodium ions out of the cell for every two positive potassium ions into the cell is the same as one positive ion leaving the cell. When positive ions leave, the inside of the cell becomes more negative, helping the cell reach its resting potential of around –70mV.
The sodium potassium-pump is used in order to establish the negative resting potential in neurons. Since both sodium and potassium ions are positively charged, there needs to be more ions leaving the cell compared to ions entering. The pump accomplishes this by pumping three sodium ions out of the cell, while pumping two potassium ions into the cell. This loss of positive charge inside the cell results in the negative resting potential of neurons.
Thank about the net transfer of ions. Three positive sodium ions out of the cell for every two positive potassium ions into the cell is the same as one positive ion leaving the cell. When positive ions leave, the inside of the cell becomes more negative, helping the cell reach its resting potential of around –70mV.
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What is the name of the process that results in a positive voltage inside the neuron?
What is the name of the process that results in a positive voltage inside the neuron?
In the beginning of an action potential voltage-gated sodium channels begin to open, allowing sodium ions to rush into the cell. This influx of positive ions results in a change in the polarity of the cell, making the voltage become positive inside the cell. This process is called depolarization.
Hyperpolarization comes after depolarization, and is caused by potassium ions leaving the cell interior. The removal of these positive ions causes the cell to become more negative than the resting potential.
Repolarization is the final process to return the cell to its resting potential. The sodium-potassium pump brings potassium ions back into the cell and removes the sodium ions, returning the cell to its normal resting state.
In the beginning of an action potential voltage-gated sodium channels begin to open, allowing sodium ions to rush into the cell. This influx of positive ions results in a change in the polarity of the cell, making the voltage become positive inside the cell. This process is called depolarization.
Hyperpolarization comes after depolarization, and is caused by potassium ions leaving the cell interior. The removal of these positive ions causes the cell to become more negative than the resting potential.
Repolarization is the final process to return the cell to its resting potential. The sodium-potassium pump brings potassium ions back into the cell and removes the sodium ions, returning the cell to its normal resting state.
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What are action potentials?
What are action potentials?
Action potentials are electrical signals transmitted by neurons. When a neuron is stimulated, a signal is transmitted down the axon. This signal is the action potential.
An action potential in a neuron can help to stimulate a muscle to contract, but the muscle itself will not conduct an action potential.
Action potentials are electrical signals transmitted by neurons. When a neuron is stimulated, a signal is transmitted down the axon. This signal is the action potential.
An action potential in a neuron can help to stimulate a muscle to contract, but the muscle itself will not conduct an action potential.
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Which structure of the neuron is myelinated to promote propogation of the action potential?
Which structure of the neuron is myelinated to promote propogation of the action potential?
The axon is wrapped in fatty bundles called myelin sheaths that promote fast transmission of an electrical signal. The other structures listed here are not myelinated.
The axon is wrapped in fatty bundles called myelin sheaths that promote fast transmission of an electrical signal. The other structures listed here are not myelinated.
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Consider a neuron with a resting membrane potential of 
.
Which of the following membrane potential values is likely to be the membrane potential of this neuron during its refractory period?
Consider a neuron with a resting membrane potential of
Which of the following membrane potential values is likely to be the membrane potential of this neuron during its refractory period?
The refractory period occurs when the cell repolarizes/hyperpolzarizes beyond the resting potential; that is, the membrane potential drops to a value more negative than when it is at rest. This prevents the firing of another action potential immediately after one has been fired. The other values represent the resting potential (
), the threshold (
), and values that are more positive, and are therefore incorrect.
The refractory period occurs when the cell repolarizes/hyperpolzarizes beyond the resting potential; that is, the membrane potential drops to a value more negative than when it is at rest. This prevents the firing of another action potential immediately after one has been fired. The other values represent the resting potential (
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What causes the hyperpolarization during an action potential?
What causes the hyperpolarization during an action potential?
As an action potential begins, there's a rapid influx of sodium in to cell, causing the cell's membrane potential to rapidly increase, depolarizing the cell. Once the cell has reached its action potential peak, the sodium channels begin to close. This closing activates the potassium channels. These channels allow potassium to leave the cell. Since potassium is a positive ion, as it leaves, the cell's membrane potential becomes more negative, repolarizing. The slight dip in the action potential curve, labeled as hyperpolarization, is result of the potassium channels lagging to close, and potassium loss is "overshot". As a result, too much potassium lost from the cell will cause the cell's potential to become more negative relative to its normal potential.
As an action potential begins, there's a rapid influx of sodium in to cell, causing the cell's membrane potential to rapidly increase, depolarizing the cell. Once the cell has reached its action potential peak, the sodium channels begin to close. This closing activates the potassium channels. These channels allow potassium to leave the cell. Since potassium is a positive ion, as it leaves, the cell's membrane potential becomes more negative, repolarizing. The slight dip in the action potential curve, labeled as hyperpolarization, is result of the potassium channels lagging to close, and potassium loss is "overshot". As a result, too much potassium lost from the cell will cause the cell's potential to become more negative relative to its normal potential.
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An action potential is generally driven by the movement of which two ions?
An action potential is generally driven by the movement of which two ions?
Action potentials are largely due to the movements of potassium 
and sodium 
across a membrane. While other ions and neurotransmitters can affect action potential firing, the movements of these two ions have the greatest effect on a neuron firing.
Action potentials are largely due to the movements of potassium
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Once an action potential arrives at the synaptic bud, what kind of ion channels open?
Once an action potential arrives at the synaptic bud, what kind of ion channels open?
As an action potential is essentially an electrical current, it makes sense for it to open voltage-gated channels. Specifically, voltage-gated calcium channels are opened to allow calcium ions to flow into the cell and bind to synaptic vesicles.
As an action potential is essentially an electrical current, it makes sense for it to open voltage-gated channels. Specifically, voltage-gated calcium channels are opened to allow calcium ions to flow into the cell and bind to synaptic vesicles.
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Which of the following is an effect of the sympathetic nervous system?
Which of the following is an effect of the sympathetic nervous system?
The sympathetic nervous system is responsible for stress responses, while the parasympathetic nervous system is responsible for resting responses. The sympathetic nervous system causes increased heart rate, pupil dilation, suppressed digestion, inhibited salivation, and dilated bronchi.
The sympathetic nervous system is responsible for stress responses, while the parasympathetic nervous system is responsible for resting responses. The sympathetic nervous system causes increased heart rate, pupil dilation, suppressed digestion, inhibited salivation, and dilated bronchi.
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What is the name of the structure on a neuron that receives eletrical signals from other neurons and cells?
What is the name of the structure on a neuron that receives eletrical signals from other neurons and cells?
The most basic anatomy for a neuron involves three structures: a soma, a dendrite, and an axon. The dendrite receives an electrical impulse and sends it to the cell body, or soma. The axon will then send the action potential towards its synapse with another neuron. The axon hillock is a wider region of the axon where the soma and axon join together.
While every neuron will have only one soma and one axon, some neurons have several dendrites. This means that a neuron can receive information from several different locations through different dendrites, but can only send it in one direction along the single axon.
The most basic anatomy for a neuron involves three structures: a soma, a dendrite, and an axon. The dendrite receives an electrical impulse and sends it to the cell body, or soma. The axon will then send the action potential towards its synapse with another neuron. The axon hillock is a wider region of the axon where the soma and axon join together.
While every neuron will have only one soma and one axon, some neurons have several dendrites. This means that a neuron can receive information from several different locations through different dendrites, but can only send it in one direction along the single axon.
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The autonomic nervous system is a subdivision of which division of the nervous system?
The autonomic nervous system is a subdivision of which division of the nervous system?
The nervous system has two major divisions: the central nervous system and the peripheral nervous system. The peripheral nervous system is further divided into the somatic nervous system and the autonomic nervous system. The autonomic nervous system can then be divided into the sympathetic and parasympathetic branches.
General: Central and Peripheral
Peripheral: Somatic and Autonomic
Autonomic: Sympathetic and Parasympathetic
The nervous system has two major divisions: the central nervous system and the peripheral nervous system. The peripheral nervous system is further divided into the somatic nervous system and the autonomic nervous system. The autonomic nervous system can then be divided into the sympathetic and parasympathetic branches.
General: Central and Peripheral
Peripheral: Somatic and Autonomic
Autonomic: Sympathetic and Parasympathetic
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Innervation of the parasympathetic nervous system will NOT result in which of the following responses?
Innervation of the parasympathetic nervous system will NOT result in which of the following responses?
The parasympathetic nervous system is responsible for the "rest and digest" functions of the body. The sympathetic nervous system is associated with "fight or flight" responses in the body. Increased blood flow to skeletal muscles is a common result of the sympathetic nervous system being stimulated, not the parasympathetic nervous system.
The parasympathetic nervous system is responsible for the "rest and digest" functions of the body. The sympathetic nervous system is associated with "fight or flight" responses in the body. Increased blood flow to skeletal muscles is a common result of the sympathetic nervous system being stimulated, not the parasympathetic nervous system.
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If the vagus nerve is responsible for slowing down the heart rate, in which division of the nervous system would it be found?
If the vagus nerve is responsible for slowing down the heart rate, in which division of the nervous system would it be found?
The vagus nerve is responsible for slowing down the heart rate. It also increases digestive activity. Knowing this, we can conclude that the vagus nerve has a "rest and digest" function in the body. This means that it is part of the parasympathetic nervous system.
The sympathetic nervous system is responsible for stress responses, or "fight or flight." The somatic nervous system is under voluntary control, while the autonomic nervous system is involuntary. Both the sympathetic and parasympathetic divisions fall under the autonomic umbrella. The central nervous system includes only the brain and spinal cord.
The vagus nerve is responsible for slowing down the heart rate. It also increases digestive activity. Knowing this, we can conclude that the vagus nerve has a "rest and digest" function in the body. This means that it is part of the parasympathetic nervous system.
The sympathetic nervous system is responsible for stress responses, or "fight or flight." The somatic nervous system is under voluntary control, while the autonomic nervous system is involuntary. Both the sympathetic and parasympathetic divisions fall under the autonomic umbrella. The central nervous system includes only the brain and spinal cord.
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In a reflex arc, which part of the pathway serves as the integrating center?
In a reflex arc, which part of the pathway serves as the integrating center?
Reflex arcs are unique neural pathways due to the fact they are constructed to cause voluntary muscles to move without a stimulus being integrated in the brain. Instead, the integration of the stimulus occurs in the spinal cord, where an efferent signal is immediately created towards the voluntary muscle.
Reflex arcs are unique neural pathways due to the fact they are constructed to cause voluntary muscles to move without a stimulus being integrated in the brain. Instead, the integration of the stimulus occurs in the spinal cord, where an efferent signal is immediately created towards the voluntary muscle.
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Which of the following divisions of the nervous system is responsible for the "fight or flight" response?
Which of the following divisions of the nervous system is responsible for the "fight or flight" response?
The sympathetic nervous system is responsible for the "fight or flight" response. The parasympathetic nervous system does the opposite (rest and digest). The enteric nervous system helps with digestion. The remaining two answer choices are too broad and do not answer the question as well as the sympathetic nervous system. Note that the sympathetic and parasympathetic nervous systems are branches of the autonomic nervous system, which itself is a branch of the parasympathetic nervous system.
The sympathetic nervous system is responsible for the "fight or flight" response. The parasympathetic nervous system does the opposite (rest and digest). The enteric nervous system helps with digestion. The remaining two answer choices are too broad and do not answer the question as well as the sympathetic nervous system. Note that the sympathetic and parasympathetic nervous systems are branches of the autonomic nervous system, which itself is a branch of the parasympathetic nervous system.
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Where do neurotransmitters attach following release into the synaptic cleft?
Where do neurotransmitters attach following release into the synaptic cleft?
Vesicles of neurotransmitter are located at the axon terminal of the presynaptic neuron. Upon stimulation, they are released into the synapse and flow across the gap between neurons. Neurotransmitters attach to receptors located on the postsynaptic membrane after being released into the synaptic cleft. This allows the action potential to continue on to the next neuron.
Vesicles of neurotransmitter are located at the axon terminal of the presynaptic neuron. Upon stimulation, they are released into the synapse and flow across the gap between neurons. Neurotransmitters attach to receptors located on the postsynaptic membrane after being released into the synaptic cleft. This allows the action potential to continue on to the next neuron.
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Dendrites have receptors that produce electrical signals when they bind with which of the following?
Dendrites have receptors that produce electrical signals when they bind with which of the following?
In the neuron, dendrites respond to the chemical neurotransmitters released by other local neurons. These dendrites have receptors in their membranes that bind specific neurotransmitters and produce electrical signals as a result of this binding. Binding of a neurotransmitter can either excite or inhibit the neuron, influencing its ability to transmit a signal.
A hormone is a chemical that is synthesized by one group of cells, secreted, and then carried in the bloodstream to other cells whose activity is influenced by reception of the hormone. An electrolyte is a solutution that conducts electricity and generally contains ions. Enzymes are proteins that speed up chemical reactions. Proteins are organic molecules composed of amino acids that are necessary for growth and repair of tissues.
In the neuron, dendrites respond to the chemical neurotransmitters released by other local neurons. These dendrites have receptors in their membranes that bind specific neurotransmitters and produce electrical signals as a result of this binding. Binding of a neurotransmitter can either excite or inhibit the neuron, influencing its ability to transmit a signal.
A hormone is a chemical that is synthesized by one group of cells, secreted, and then carried in the bloodstream to other cells whose activity is influenced by reception of the hormone. An electrolyte is a solutution that conducts electricity and generally contains ions. Enzymes are proteins that speed up chemical reactions. Proteins are organic molecules composed of amino acids that are necessary for growth and repair of tissues.
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Which of the following is released when an axon is excited and acts by inhibiting or exciting a target cell?
Which of the following is released when an axon is excited and acts by inhibiting or exciting a target cell?
A neurotransmitter is a chemical agent that relays messages from one nerve cell to the next. An enzyme is a protein that causes other substances to change. Enzymes regulate the rate of chemical reactions. An electrolyte is a substance that, when dissolved, forms electrically charged particles. Ions have lost one or more electrons and have a positive charge, or gained one or more electrons and have a negative charge. In aqueous solutions, ions are called electrolytes because they permit the solution to conduct electricity. Interleukin is a type of protein that enables communication among cells active in inflammation or the specific immune response.
A neurotransmitter is a chemical agent that relays messages from one nerve cell to the next. An enzyme is a protein that causes other substances to change. Enzymes regulate the rate of chemical reactions. An electrolyte is a substance that, when dissolved, forms electrically charged particles. Ions have lost one or more electrons and have a positive charge, or gained one or more electrons and have a negative charge. In aqueous solutions, ions are called electrolytes because they permit the solution to conduct electricity. Interleukin is a type of protein that enables communication among cells active in inflammation or the specific immune response.
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Which of the following ions is required for vesicles containing neurotransmitters to be released into the synaptic cleft?
Which of the following ions is required for vesicles containing neurotransmitters to be released into the synaptic cleft?
Vesicles containing neurotransmitters must bind to the membrane at the axon terminal in order to release their contents into the synapse. This binding is dependent upon an influx of calcium ions that occurs with an action potential. The other ions listed are important for other parts of the action potential, but it is calcium that is crucial for this particular step.
Vesicles containing neurotransmitters must bind to the membrane at the axon terminal in order to release their contents into the synapse. This binding is dependent upon an influx of calcium ions that occurs with an action potential. The other ions listed are important for other parts of the action potential, but it is calcium that is crucial for this particular step.
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Fill in the blanks with the best answers:
__________ gated potassium channels are the primary mediators of __________ of the neuronal membrane. They permit the postively charged potassium ions to flow out of the cell once the peak of the action potential has been reached.
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__________ gated potassium channels are the primary mediators of __________ of the neuronal membrane. They permit the postively charged potassium ions to flow out of the cell once the peak of the action potential has been reached.
Voltage-gated potassium ion channels are responsible for bringing the membrane potential back to or below resting the potential. This is achieved when these channels open, which can only happen at very positive voltages (hence voltage-gated), and as the potassium ions rapidly leave the cell, the cell repolarizes to a negative potential.
Voltage-gated potassium ion channels are responsible for bringing the membrane potential back to or below resting the potential. This is achieved when these channels open, which can only happen at very positive voltages (hence voltage-gated), and as the potassium ions rapidly leave the cell, the cell repolarizes to a negative potential.
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