Neurophysiology Basics
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Questions and Answers

Which ion is highly concentrated outside of the cell?

  • Cl-
  • Na+ (correct)
  • Ca2+
  • K+

Which ion is highly concentrated inside of the cell?

  • Cl-
  • K+ (correct)
  • Ca2+
  • Na+

What is the resting membrane potential of a neuron?

  • -30 mV
  • -70 mV (correct)
  • -90 mV
  • -50 mV

Which cells create myelin in the central nervous system (CNS)?

<p>Oligodendrocytes (D)</p> Signup and view all the answers

What is the function of nodes of Ranvier?

<p>To transmit action potentials (A)</p> Signup and view all the answers

What is the process called when an action potential 'jumps' from node of Ranvier to node of Ranvier?

<p>Saltatory conduction (B)</p> Signup and view all the answers

What is the function of ligand-gated ion channels in the synapse?

<p>To receive and transduce signals (B)</p> Signup and view all the answers

Which type of stimuli can change the membrane potential (Vm) of a neuron?

<p>Both depolarizing and hyperpolarizing stimuli (B)</p> Signup and view all the answers

What are the three key phases of an action potential?

<p>Depolarization, repolarization, hyperpolarization (C)</p> Signup and view all the answers

What triggers the opening of voltage-gated sodium (Na+) channels?

<p>A certain threshold voltage being reached (B)</p> Signup and view all the answers

What determines the speed of action potential propagation?

<p>The diameter of the axon and myelination (C)</p> Signup and view all the answers

Which of the following is the resting membrane potential of a neuron?

<p>-70 mV (D)</p> Signup and view all the answers

Which ions are highly concentrated outside of the cell?

<p>Na+ and Cl- (A)</p> Signup and view all the answers

Which ions are highly concentrated inside of the cell?

<p>K+ (A)</p> Signup and view all the answers

What is the approximate value of the resting membrane potential (Vrest)?

<p>-70 mV (A)</p> Signup and view all the answers

What is the primary function of ligand-gated ion channels in the synapse?

<p>To allow ions to flow across the membrane in response to neurotransmitter binding (D)</p> Signup and view all the answers

What determines the speed of action potential propagation?

<p>Myelination and axon diameter (D)</p> Signup and view all the answers

What are the three key phases of an action potential?

<p>Depolarization, repolarization, hyperpolarization (B)</p> Signup and view all the answers

What triggers the opening of voltage-gated sodium (Na+) channels?

<p>Depolarization of the membrane (D)</p> Signup and view all the answers

Which type of stimuli can change the membrane potential (Vm) of a neuron?

<p>Chemical and electrical stimuli (B)</p> Signup and view all the answers

Which cells create myelin in the central nervous system (CNS)?

<p>Oligodendrocytes (A)</p> Signup and view all the answers

What triggers the opening of voltage-gated potassium (K+) channels during an action potential?

<p>Voltage gates open when Vm reaches a certain threshold voltage (A)</p> Signup and view all the answers

What is the purpose of the after-hyperpolarization (AHP) phase of an action potential?

<p>To reset the membrane potential (Vm) back to resting state (D)</p> Signup and view all the answers

What is the role of the axon initial segment (AIS) in the propagation of action potentials?

<p>To generate action potentials (A)</p> Signup and view all the answers

What determines the speed of action potential propagation?

<p>The diameter of the axon (B)</p> Signup and view all the answers

What is the purpose of the refractory period after an action potential?

<p>To prevent the backward propagation of action potentials (D)</p> Signup and view all the answers

What triggers the rising phase of an action potential?

<p>Activation gates of voltage-gated Na+ channels opening (D)</p> Signup and view all the answers

What is the function of voltage-gated sodium (Na+) channels during an action potential?

<p>To initiate the depolarization phase (C)</p> Signup and view all the answers

What is the function of voltage-gated potassium (K+) channels during an action potential?

<p>To initiate the repolarization phase (B)</p> Signup and view all the answers

What is the purpose of the undershoot/after-hyperpolarization (AHP) phase of an action potential?

<p>To reset the membrane potential (Vm) back to resting state (A)</p> Signup and view all the answers

What is the role of the axon hillock in the initiation of an action potential?

<p>To generate action potentials (C)</p> Signup and view all the answers

Which ion channels are responsible for depolarizing the postsynaptic membrane potential (Vm)?

<p>Sodium (Na+) channels (A)</p> Signup and view all the answers

Which type of potential occurs when there is a brief change in the postsynaptic membrane potential (Vm)?

<p>Postsynaptic potential (PSP) (B)</p> Signup and view all the answers

Which ion channels are responsible for hyperpolarizing the postsynaptic membrane potential (Vm)?

<p>Potassium (K+) channels (B)</p> Signup and view all the answers

Where does signal integration occur in a neuron?

<p>Axon hillock (D)</p> Signup and view all the answers

Which type of signal transmission occurs when neurotransmitters (NTs) are released into the synapse?

<p>Chemical signal (B)</p> Signup and view all the answers

What is the process called when neurotransmitters (NTs) are cleared from the synapse?

<p>All of the above (D)</p> Signup and view all the answers

Which type of receptors open in response to ligand binding and cause very fast changes in membrane potential (Vm)?

<p>Ligand-gated ion channels (A)</p> Signup and view all the answers

What is the function of myelin in the conduction of action potentials?

<p>To increase the speed of conduction (A)</p> Signup and view all the answers

What are the gaps between sections of myelin where the axon is exposed called?

<p>Nodes of Ranvier (D)</p> Signup and view all the answers

What is the process called when an action potential 'jumps' from node of Ranvier to node of Ranvier?

<p>Saltatory conduction (C)</p> Signup and view all the answers

What are the two types of cells that create myelin in the nervous system, and where are they located?

<p>Oligodendrocytes in the CNS and Schwann cells in the PNS</p> Signup and view all the answers

What are the two types of signal transmission that occur in the synapse?

<p>Electrical and chemical signal transmission</p> Signup and view all the answers

What are the gaps between sections of myelin where the axon is exposed called?

<p>Nodes of Ranvier</p> Signup and view all the answers

What triggers the opening of voltage-gated calcium channels (VGCCs) in the presynaptic terminal?

<p>Depolarization</p> Signup and view all the answers

What is the function of synaptic vesicles in the presynaptic terminal?

<p>They are filled with neurotransmitter (NT) molecules and are responsible for the release of NTs into the synapse</p> Signup and view all the answers

What is the process called when neurotransmitters (NTs) are cleared from the synapse?

<p>Neurotransmitter clearance</p> Signup and view all the answers

What are the three ways in which signal integration can occur in a neuron?

<p>Spatial summation, temporal summation, and cancellation</p> Signup and view all the answers

What is the purpose of spatial summation in signal integration?

<p>Adding up of potentials from different locations across the neuron at the axon hillock</p> Signup and view all the answers

What is the purpose of temporal summation in signal integration?

<p>Adding up of all potentials that reach the axon hillock based on time of arrival</p> Signup and view all the answers

What is the process called when an inhibitory postsynaptic potential (IPSP) spatially coincides with an excitatory postsynaptic potential (EPSP) and partially or totally cancels it out?

<p>EPSP-IPSP cancellation</p> Signup and view all the answers

What is the function of the axon hillock in the initiation of an action potential?

<p>The axon hillock is responsible for integrating incoming signals from the dendrites and deciding whether to initiate an action potential.</p> Signup and view all the answers

What is the role of the axon initial segment (AIS) in the propagation of action potentials?

<p>The axon initial segment (AIS) is responsible for generating and propagating action potentials along the axon.</p> Signup and view all the answers

What determines the speed of action potential propagation?

<p>The speed of action potential propagation is determined by the diameter of the axon and the presence of myelin sheath.</p> Signup and view all the answers

What triggers the opening of voltage-gated sodium (Na+) channels?

<p>Depolarization of the membrane to the threshold level triggers the opening of voltage-gated sodium (Na+) channels.</p> Signup and view all the answers

What triggers the opening of voltage-gated potassium (K+) channels during an action potential?

<p>The opening of voltage-gated potassium (K+) channels is triggered by the depolarization of the membrane during the rising phase of an action potential.</p> Signup and view all the answers

Which type of potential occurs when there is a brief change in the postsynaptic membrane potential (Vm)?

<p>A postsynaptic potential (PSP) occurs when there is a brief change in the postsynaptic membrane potential (Vm).</p> Signup and view all the answers

Which type of stimuli can change the membrane potential (Vm) of a neuron?

<p>Both excitatory and inhibitory stimuli can change the membrane potential (Vm) of a neuron.</p> Signup and view all the answers

Which ion is highly concentrated outside of the cell?

<p>Sodium (Na+) ion is highly concentrated outside of the cell.</p> Signup and view all the answers

Where does signal integration occur in a neuron?

<p>Signal integration occurs at the axon hillock of a neuron.</p> Signup and view all the answers

What is the resting membrane potential of a neuron?

<p>The resting membrane potential of a neuron is approximately -70 millivolts (mV).</p> Signup and view all the answers

What are the three types of ion channels that allow ions to cross the cell membrane?

<p>Leak channels, voltage-gated channels, and ligand-gated channels.</p> Signup and view all the answers

Explain the difference between depolarization and hyperpolarization.

<p>Depolarization is when the interior of the neuron becomes less negative than the resting membrane potential (Vrest). Hyperpolarization is when the interior of the neuron becomes more negative than Vrest.</p> Signup and view all the answers

What is the role of the Na+/K+ pump in maintaining consistent ionic concentrations?

<p>The Na+/K+ pump moves 2 K+ ions into the neuron and 3 Na+ ions out of the neuron using 1 molecule of ATP. This helps keep the ion concentrations constant, ensuring that the diffusive force remains unchanged over time.</p> Signup and view all the answers

What are the five distinct stages of an action potential?

<p>The five stages of an action potential are: initiation, depolarization/rising phase, repolarization/falling phase, after-hyperpolarization/undershoot, and return to rest.</p> Signup and view all the answers

What triggers the opening of voltage-gated Na+ channels during an action potential?

<p>Voltage-gated Na+ channels open when the membrane potential (Vm) reaches a certain threshold voltage.</p> Signup and view all the answers

Explain the concept of frequency-coding in action potentials.

<p>Frequency-coding refers to the increase in the number of action potentials produced in response to increased stimulus intensity. Higher stimulus intensity leads to more action potentials being generated.</p> Signup and view all the answers

What determines the speed of action potential propagation?

<p>The speed of action potential propagation, also known as conduction velocity, is determined by the diameter of the axon and the presence of myelination.</p> Signup and view all the answers

What is the purpose of the refractory period after an action potential?

<p>The refractory period is a period of time after an action potential where the membrane is unresponsive to firing additional action potentials. This allows the neuron to reset and ensures that action potentials travel in a unidirectional manner.</p> Signup and view all the answers

What is the role of nodes of Ranvier in the conduction of action potentials?

<p>Nodes of Ranvier are the gaps between sections of myelin where the axon is exposed. They play a crucial role in the conduction of action potentials by allowing the action potential to 'jump' from one node to another, which speeds up the propagation of the action potential.</p> Signup and view all the answers

Where does signal integration occur in a neuron?

<p>Signal integration occurs at the axon initial segment (AIS) next to the axon hillock. It is here that the neuron determines whether the incoming signals are strong enough to generate an action potential.</p> Signup and view all the answers

Match the following ions with their location of high concentration in relation to a neuron:

<p>Na+ = Highly concentrated outside of the cell K+ = Highly concentrated inside of the cell Cl- = Highly concentrated outside of the cell</p> Signup and view all the answers

Match the following terms with their appropriate definitions:

<p>Neurotransmission = Process of transmitting information within neuronal cells through chemical and electrical signals Resting potential = The state of a neuron when no inputs are acting upon it, usually at about $-70$ millivolts Membrane potential = The charge difference between the interior and the exterior of a neuron</p> Signup and view all the answers

Match the following processes with their descriptions:

<p>Action Potential = Brief change in the postsynaptic membrane potential Signal Integration = Process in which incoming signals from many neurons integrate to influence firing rate of a neuron Conduction Velocity = Determines the speed of action potential propagation</p> Signup and view all the answers

Match the following potentials with their values:

<p>Resting membrane potential (Vrest) = Approximately $-70$ millivolts</p> Signup and view all the answers

Match the terms with their definitions:

<p>Neurophysiology = Study of chemical and electrical signals within neuronal cells to process and transmit information Myelination = Process that increases conduction velocity Propagation = Process of transmitting an action potential from one location to another</p> Signup and view all the answers

Match the terms with their definitions:

<p>Plasma or cell membrane = Separates intracellular environment from extracellular environment Neuron's interior = Usually more negatively charged than the exterior space Neurotransmission process = Provides baseline knowledge of neurotransmission</p> Signup and view all the answers

Match the terms with their definitions:

<p>Neurophysiology = Study of how neurons process and transmit information Action Potential = Process that allows neurons to transmit information over long distances Signal Integration = Influences the firing rate of a neuron</p> Signup and view all the answers

Match the terms with their definitions:

<p>Membrane Potential (Vm) = Electrical charge difference between the interior and the exterior of a neuron Resting Potential (Vrest) = State of a neuron when no inputs are acting upon it Action Potential = Brief change in the postsynaptic membrane potential</p> Signup and view all the answers

Match the following ions with their high concentration locations:

<p>Na+ = Outside of the cell K+ = Inside of the cell Cl- = Outside of the cell</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Membrane Potential = The electrical potential difference between the inside and the outside of a neuron Resting Potential = The stable, negative charge of a neuron when it is at rest Action Potential = The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell</p> Signup and view all the answers

Match the following terms with their definitions in the context of neuronal action potential:

<p>Depolarization = Interior of neuron becomes less negative than Vrest, primarily due to Na+ currents Hyperpolarization = Interior of neuron becomes more negative than Vrest, primarily due to K+ and Cl- currents Afterhyperpolarization/Undershoot = Brief period of hyperpolarization after an action potential Refractory period = Period after an action potential where the membrane is unresponsive to firing additional APs</p> Signup and view all the answers

Match the following phases of an action potential with their descriptions:

<p>Depolarization/Rising Phase = Interior of neuron rapidly becomes more positively charged Repolarization/Falling phase = Interior of neuron rapidly returns to negatively charged status After-hyperpolarization/Undershoot = Neuron bypasses Vrest and is briefly hyperpolarized Return to rest = The neuron returns to Vrest</p> Signup and view all the answers

Match the following ion channels with their functions during an action potential:

<p>Voltage-gated Na+ channels (VGNC) = Trigger the rising phase by opening quickly at threshold Voltage-gated K+ channels (VGKC) = Trigger repolarization and hyperpolarization by slowly opening and closing Leak channels = Allow ions to cross the membrane, always open Gated channels = Open or close in response to environmental signals</p> Signup and view all the answers

Match the following terms with their definitions in the context of action potential propagation:

<p>Propagation = The movement of APs as Na+ spreads out and triggers APs in neighboring sections of the axon Axon initial segment (AIS) = The site where APs originate, next to the axon hillock Unidirectional travel = APs travel from AIS to axon terminals due to the refractory period Conduction velocity = The speed of AP propagation, determined by axon diameter and myelination</p> Signup and view all the answers

Match the following properties of the action potential with their descriptions:

<p>All-or-none principle = Neuron either fires or does not, and AP amplitude is always the same Frequency-coding = Increased stimulus intensity results in more APs produced Refractory period = Period after an AP where the membrane is unresponsive to firing additional APs Propagation = APs are not static, Na+ spreads out as it enters neuron, triggering APs in neighboring sections of the axon</p> Signup and view all the answers

Match the following terms related to ion movement with their definitions:

<p>Vm Concentration gradients = Presence of different ion concentrations across the cell membrane Diffusive force = Pushes ions down their concentration gradient Na+/K+ pump = Keeps ion concentrations constant by moving 2 K+ in and 3 Na+ out of the neuron using 1 molecule of ATP Ion channels = Allow ions to cross the membrane</p> Signup and view all the answers

Match the following terms with their definitions in the context of changes in Vm:

<p>Depolarization = Interior becomes less negative than Vrest, primarily due to Na+ currents Hyperpolarization = Interior becomes more negative than Vrest, primarily due to K+ and Cl- currents Graded potentials = Changes in Vm that are local and graded, decay back to Vrest over time Threshold = If reached, the cell will fire an action potential</p> Signup and view all the answers

Match the following types of ion channels with their functions:

<p>Voltage-gated Na+ channels (VGNC) = Open quickly at threshold, triggering a strong depolarization Voltage-gated K+ channels (VGKC) = Open and close slowly, triggering a strong hyperpolarization Leak channels = Always open, allowing ions to cross the membrane Gated channels = Open or close in response to environmental signals</p> Signup and view all the answers

Match the following terms with their definitions in the context of the neuron's response to stimuli:

<p>Local = Potential travels away from its source and across the membrane, it decays Graded = Larger stimuli result in larger responses and vice versa Threshold = If reached, the cell will fire an action potential Refractory period = Period after an AP where the membrane is unresponsive to firing additional APs</p> Signup and view all the answers

Match the following terms with their definitions in the context of the action potential:

<p>Initiation = Neuron is depolarized to threshold Depolarization/Rising Phase = Interior of neuron rapidly becomes more positively charged After-hyperpolarization/Undershoot = Neuron bypasses Vrest and is briefly hyperpolarized Return to rest = The neuron returns to Vrest</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Oligodendrocytes = Cells responsible for producing myelin in the Central Nervous System Internodes = Sections of axon covered by myelin Nodes of Ranvier = Gaps between sections of myelin where the axon is exposed Myelination = The process that allows for faster conduction of action potentials</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Synaptic vesicles = Small, spherical organelles located in the presynaptic terminal filled with neurotransmitter (NT) molecules Voltage-gated calcium channels (VGCCs) = Channels expressed densely on presynaptic terminal, which open upon depolarization leading to Ca2+ influx Neurotransmitter (NT) = Endogenous chemical specialized for transmitting information between neurons Receptors = Proteins that receive and transduce signals, typically located postsynaptically</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Excitatory postsynaptic potential (EPSP) = Depolarizing postsynaptic potential that pushes the postsynaptic Vm toward the AP threshold Inhibitory postsynaptic potential (IPSP) = Hyperpolarizing postsynaptic potential that pushes the postsynaptic Vm away from the AP threshold Spatial summation = Adding up of potentials from different locations across the neuron at the axon hillock Temporal summation = Adding up of all potentials that reach the axon hillock based on time of arrival</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Degradation = Rapid breakdown/inactivation of NT by an enzyme Reuptake = Process where NT is reabsorbed by transporters in presynaptic terminal to be reused Diffusion = Process where NT molecules diffuse out of the synapse EPSP-IPSP cancellation = Process where an IPSP spatially coincides with an EPSP and partially or totally cancels it out</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Saltatory conduction = Process where the action potential appears to 'jump' from node of Ranvier to node of Ranvier Axon hillock = Location where integration of signals happens Schwann cells = Cells responsible for producing myelin in the Peripheral Nervous System Ligand-gated ion channels = Receptors that open in response to ligand binding and cause very fast changes in membrane potential</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Calcium ions (Ca2+) = Ions highly concentrated outside the neuron Depolarization = Process that opens voltage gate on VGCCs leading to Ca2+ influx Exocytosis = Process where vesicles fuse with membrane and NTs flow down concentration gradient into synapse Endogenous = Naturally occurring, originating from organism itself</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Signal integration = How postsynaptic potentials interact on the postsynaptic neuron to influence its firing Binding sites = Areas on receptors dedicated to detecting/binding NTs Internodes = Sections of axon covered by myelin Nodes of Ranvier = Gaps between sections of myelin where the axon is exposed</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Neurotransmitter (NT) = Endogenous chemical specialized for transmitting information between neurons Receptors = Proteins that receive and transduce signals, typically located postsynaptically Synaptic vesicles = Small, spherical organelles located in the presynaptic terminal filled with neurotransmitter (NT) molecules Voltage-gated calcium channels (VGCCs) = Channels expressed densely on presynaptic terminal, which open upon depolarization leading to Ca2+ influx</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Excitatory postsynaptic potential (EPSP) = Depolarizing postsynaptic potential that pushes the postsynaptic Vm toward the AP threshold Inhibitory postsynaptic potential (IPSP) = Hyperpolarizing postsynaptic potential that pushes the postsynaptic Vm away from the AP threshold Spatial summation = Adding up of potentials from different locations across the neuron at the axon hillock Temporal summation = Adding up of all potentials that reach the axon hillock based on time of arrival</p> Signup and view all the answers

Match the following terms with their correct definitions:

<p>Degradation = Rapid breakdown/inactivation of NT by an enzyme Reuptake = Process where NT is reabsorbed by transporters in presynaptic terminal to be reused Diffusion = Process where NT molecules diffuse out of the synapse EPSP-IPSP cancellation = Process where an IPSP spatially coincides with an EPSP and partially or totally cancels it out</p> Signup and view all the answers

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