Neurophysiology Basics

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

<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

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

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

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

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

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

<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

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

<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

<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

<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

<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

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

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

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

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

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

<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

<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

<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

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

<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

<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

<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

<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

<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

<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

<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

<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

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

<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

<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

<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

<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

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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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

<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