Neuroscience: Action Potential and Propagation

-55 mV

Voltage-dependent Na+ channels

By jumping from node to node through saltatory conduction.

<p>They allow for ion exchange and retriggering of action potentials.</p> Signup and view all the answers

<p>The signal may decrease due to decremental conduction.</p> Signup and view all the answers

<p>They propagate action potentials less efficiently and are slower.</p> Signup and view all the answers

<p>Na+-K+ pumps only operate at the nodes.</p> Signup and view all the answers

<p>It refers to the sequential triggering of action potentials along the neuron.</p> Signup and view all the answers

<p>To communicate between neurons by binding to specific receptors.</p> Signup and view all the answers

<p>Ca2+ ions trigger the fusion of synaptic vesicles with the membrane, releasing neurotransmitters.</p> Signup and view all the answers

<p>It is the space between neurons where neurotransmitters are released and bind to receptors.</p> Signup and view all the answers

<p>They flow into the neuron through voltage-dependent channels.</p> Signup and view all the answers

<p>The opening of Ca2+ channels leads to neurotransmitter release into the synaptic cleft.</p> Signup and view all the answers

<p>They bind to specific receptors and influence the neuron's electrical state.</p> Signup and view all the answers

<p>It's the process where synaptic vesicles merge with the membrane to release neurotransmitters.</p> Signup and view all the answers

<p>It conducts important information rapidly from one end to another.</p> Signup and view all the answers

<p>It ensures that neurotransmitters bind only to their respective receptors, allowing precise signaling.</p> Signup and view all the answers

<p>The concentration gradient and voltage gradient drive Ca2+ into the neuron.</p> Signup and view all the answers

<p>Historical drug use established foundational knowledge and principles that inform current drug development processes and practices.</p> Signup and view all the answers

<p>Politics has influenced drug legalization, often prioritizing tax income and regulatory frameworks over purely therapeutic considerations.</p> Signup and view all the answers

<p>Isolating active ingredients can lead to increased potency and precision in treatment but may also result in unforeseen side effects and dependence.</p> Signup and view all the answers

<p>Societal mores dictate the cultural perception of certain substances, determining their acceptance or rejection based on prevailing values and beliefs.</p> Signup and view all the answers

<p>The re-scheduling initiative may pave the way for increased research, accessibility, and a shift in public perception regarding therapeutic drug use.</p> Signup and view all the answers

<p>Cannabis sativa, Cannabis indica, and Cannabis ruderalis.</p> Signup and view all the answers

<p>Marijuana is defined as a cannabis plant containing more than 0.3% THC.</p> Signup and view all the answers

<p>Hemp contains less than 0.3% THC.</p> Signup and view all the answers

<p>George Washington and Thomas Jefferson.</p> Signup and view all the answers

<p>A 2,700-year-old grave contained 789 grams of cannabis.</p> Signup and view all the answers

<p>Delta-9-tetrahydrocannabinol (Δ9-THC).</p> Signup and view all the answers

<p>At least 489 distinct compounds.</p> Signup and view all the answers

<p>CBD is a non-psychoactive cannabinoid derived from both hemp and marijuana plants.</p> Signup and view all the answers

<p>It suggests a reluctance to explore new methods and compounds.</p> Signup and view all the answers

<p>Cannabaceae.</p> Signup and view all the answers

<p>He investigated cannabis for rheumatism, tetanus, cholera, pain relief, muscle relaxation, migraines, and epilepsy.</p> Signup and view all the answers

<p>Political propaganda associated cannabis with abuse and crime, leading to heavy taxation and its classification as a Schedule 1 substance.</p> Signup and view all the answers

<p>Sir William Osler advocated that Cannabis indica was probably the most satisfactory remedy for migraines.</p> Signup and view all the answers

<p>The Marihuana Tax Act imposed heavy taxes and fines, effectively restricting the medical use of cannabis.</p> Signup and view all the answers

<p>The 1960s counterculture stigmatized marijuana, associating it with psychedelic and anti-establishment movements.</p> Signup and view all the answers

<p>The Department filed a patent for cannabinoids as antioxidants and neuroprotectants.</p> Signup and view all the answers

<p>Some historians believe prominent businesses sought to reduce the hemp industry's size to promote newer products like nylon.</p> Signup and view all the answers

<p>The classification indicated that marijuana had no medicinal benefit, severely restricting research on its therapeutic uses.</p> Signup and view all the answers

<p>The Bureau associated marijuana use with psychosis, mental deterioration, addiction, and violent crimes.</p> Signup and view all the answers

<p>The Journal continued to recommend oral preparations of cannabis for migraine treatment despite the growing stigma.</p> Signup and view all the answers

<p>To allow the in-flow of Na+ and Ca2+, leading to depolarization.</p> Signup and view all the answers

<p>When activated, GABAA receptors allow the in-flow of Cl-, resulting in hyperpolarization and inhibition of neuronal activity.</p> Signup and view all the answers

<p>Two molecules of acetylcholine (ACh) are necessary for activation.</p> Signup and view all the answers

<p>Ligand-gated ion channels are activated by the binding of specific neurotransmitters, while voltage-gated channels are activated by changes in membrane potential.</p> Signup and view all the answers

<p>Monoamines (e.g., dopamine, serotonin) and amino acids (e.g., glutamate, GABA).</p> Signup and view all the answers

<p>Kv channels allow the flow of K+ out of the neuron during repolarization.</p> Signup and view all the answers

<p>P2X receptors are activated by ATP and allow the inflow of Na+ and Ca2+.</p> Signup and view all the answers

<p>The three subtypes are NMDA, AMPA, and a third subtype not specified.</p> Signup and view all the answers

<p>Ligand-gated channels open and close depending on the presence of specific ligands.</p> Signup and view all the answers

<p>They allow in-flow of Na+ and K+, leading to depolarization of the postsynaptic neuron.</p> Signup and view all the answers

<p>P2X receptors permit the influx of Na+ and Ca2+ ions.</p> Signup and view all the answers

<p>Kv channels are mainly activated by high positive voltages, with some exceptions.</p> Signup and view all the answers

<p>The diversity allows for specificity in signaling pathways and responses to different ligands.</p> Signup and view all the answers

<p>Ca2+ influx through these receptors contributes to depolarization and various intracellular processes.</p> Signup and view all the answers

<p>Ligand-gated ion channels open in response to ligand binding, allowing specific ions to pass through.</p> Signup and view all the answers

<p>TRP channels are involved in detecting environmental stimuli such as temperature and pain, acting as transducers.</p> Signup and view all the answers

<p>Ligand-gated channels open in response to the binding of a chemical messenger, unlike voltage-gated channels that respond to changes in membrane potential.</p> Signup and view all the answers

<p>GABAA receptors are ionotropic receptors that mediate fast inhibitory neurotransmission by allowing Cl- ions to enter the neuron, hyperpolarizing it.</p> Signup and view all the answers

<p>Nicotinic acetylcholine receptors are ligand-gated ion channels that open upon acetylcholine binding, allowing Na+ influx that leads to muscle contraction.</p> Signup and view all the answers

<p>Neurotransmitters can be broadly classified as excitatory or inhibitory, with examples including glutamate and GABA, respectively.</p> Signup and view all the answers

<p>Ionotropic receptors allow rapid ion flow upon ligand binding, enabling quick synaptic responses within 10-50 ms.</p> Signup and view all the answers

<p>The conformational change allows the ion channel to open and ions to flow, facilitating neuronal communication.</p> Signup and view all the answers

<p>Astrocytes participate in the reuptake of neurotransmitters from the synaptic cleft, helping to clear signals and regulate communication between neurons.</p> Signup and view all the answers

<p>Oligodendrocytes provide myelin sheaths that insulate axons, enhancing the speed of electrical impulse conduction.</p> Signup and view all the answers

<p>Neurotransmitters transmit signals by binding to receptors on post-synaptic neurons, influencing their activity.</p> Signup and view all the answers

<p>To trigger a secondary messenger system via G-proteins that modulate ion channel function indirectly.</p> Signup and view all the answers

<p>Second messengers, like cAMP and cGMP, facilitate cellular responses by altering the conformation of nearby ion channels.</p> Signup and view all the answers

<p>They provide feedback inhibition to the presynaptic neuron, regulating the production of neurotransmitters.</p> Signup and view all the answers

<p>The net inflow of positively charged ions (like Na+) leads to excitation, while the inflow of negatively charged ions (like Cl-) or outflow of positive ions (like K+) results in inhibition.</p> Signup and view all the answers

<p>Feedback mechanisms ensure that neurotransmitter levels are regulated, preventing excessive signaling or buildup in the synaptic cleft.</p> Signup and view all the answers

<p>Drugs can either inhibit or enhance neurotransmitter effects by targeting receptors, second messenger systems, or reuptake processes.</p> Signup and view all the answers

<p>Ionotropic receptors directly form ion channels that open upon neurotransmitter binding, while metabotropic receptors activate a secondary messenger system indirectly.</p> Signup and view all the answers

<p>The neuron is more likely to reach the threshold of -55 mV, triggering an action potential.</p> Signup and view all the answers

<p>TRP channels primarily function as sensors for various stimuli, enabling the cell to respond to changes in temperature, pressure, and chemical signals.</p> Signup and view all the answers

<p>Ligand-gated channels open in response to the binding of specific molecules, whereas voltage-gated channels open based on changes in membrane potential.</p> Signup and view all the answers

<p>GABAA receptors are responsible for mediating inhibitory neurotransmission, helping to regulate neuronal excitability and prevent overstimulation.</p> Signup and view all the answers

<p>When acetylcholine binds to nicotinic receptors, it causes the channels to open, allowing Na+ ions to flow into the cell, leading to depolarization.</p> Signup and view all the answers

<p>Glutamate is a neurotransmitter that primarily activates ionotropic receptors, such as NMDA and AMPA receptors.</p> Signup and view all the answers

<p>Channelopathies are diseases caused by dysfunctional ion channels, highlighting their importance in various physiological processes.</p> Signup and view all the answers

<p>Activation of TRP channels can facilitate the sensation of pain by responding to noxious stimuli and transmitting signals to the nervous system.</p> Signup and view all the answers

<p>GABAA receptor agonists typically produce sedative effects by enhancing inhibitory neurotransmission.</p> Signup and view all the answers

<p>Ligand-gated channels allow rapid changes in ion flow that facilitate the transmission of signals between neurons.</p> Signup and view all the answers

<p>Nicotinic acetylcholine receptors mediate excitatory neurotransmission by allowing the influx of cations, primarily Na+, leading to depolarization.</p> Signup and view all the answers

<p>Ionotropic receptors directly allow ions to flow through their channel upon ligand binding, resulting in immediate changes in membrane potential. In contrast, metabotropic receptors activate intracellular signaling cascades via G-proteins, leading to slower and more prolonged physiological effects.</p> Signup and view all the answers

<p>NMDA receptors are considered ionotropic because they form ion channels that open upon glutamate binding, allowing Na+, Ca2+, and K+ ions to flow. They uniquely require glycine as a co-agonist in addition to glutamate for activation.</p> Signup and view all the answers

<p>GABAA is an ionotropic receptor that allows Cl- influx, leading to hyperpolarization and inhibition, while GABAB is a metabotropic receptor that activates intracellular second messenger pathways, resulting in slower inhibitory effects without direct ion flow.</p> Signup and view all the answers

<p>Ligand-gated channels, like ionotropic receptors, generate rapid responses by directly allowing ion flow upon ligand binding. In contrast, G-protein coupled receptors, or metabotropic receptors, initiate slower responses by activating intracellular signaling pathways through G-proteins.</p> Signup and view all the answers

<p>Serotonin 5-HT3 receptors are ionotropic receptors that, when activated by serotonin, allow the flow of Na+ and Ca2+ ions, leading to depolarization. This classification as an ionotropic receptor allows for fast synaptic transmission.</p> Signup and view all the answers

<p>Ionotropic receptors open ion channels directly upon binding of a ligand, while metabotropic receptors activate signaling pathways through second messengers.</p> Signup and view all the answers

<p>Ionotropic receptors are associated with faster synaptic responses.</p> Signup and view all the answers

<p>An example of an ionotropic receptor is the GABAA receptor, which allows Cl- ions to flow in, leading to hyperpolarization of the neuron.</p> Signup and view all the answers

<p>Second messengers amplify the signal initiated by ligand binding and can have various downstream effects, including changes in gene expression.</p> Signup and view all the answers

<p>Metabotropic receptors can initiate a variety of intracellular pathways and functions beyond ion channel opening, enabling complex signaling networks.</p> Signup and view all the answers

<p>Targeting ionotropic receptors can lead to rapid effects on synaptic transmission, making them suitable for acute interventions.</p> Signup and view all the answers

<p>Ionotropic receptors have activation times in milliseconds, while metabotropic receptors typically take seconds to elicit effects.</p> Signup and view all the answers

<p>Nicotinic acetylcholine receptors primarily allow Na+ ions to flow into the cell upon activation.</p> Signup and view all the answers

<p>Metabotropic receptor activation involves complex signaling pathways, which can continue to exert effects long after the initial ligand binding.</p> Signup and view all the answers

<p>Ionotropic receptors contain a binding site and an ion channel combined, while metabotropic receptors are linked to G-proteins and initiate longer-lasting responses.</p> Signup and view all the answers

<p>They facilitate communication by allowing ions to flow directly through their channel upon ligand binding, resulting in rapid synaptic responses.</p> Signup and view all the answers

<p>Metabotropic receptors activate intracellular signaling pathways via G-proteins, leading to indirect modulation of ion channels and cellular responses.</p> Signup and view all the answers

<p>Drugs often target the receptor binding site or the ion channel itself to influence the ion flow and thus modulate neuronal excitability.</p> Signup and view all the answers

<p>The conformational change upon ligand binding opens the ion channel, allowing specific ions to flow in or out, which is essential for action potential generation.</p> Signup and view all the answers

<p>Ligand binding activates G-proteins, which then trigger various intracellular signaling cascades, affecting multiple cellular functions.</p> Signup and view all the answers

<p>Ionotropic receptors respond very quickly, typically within 10-50 milliseconds, due to their direct coupling with ion channels.</p> Signup and view all the answers

<p>Activation of metabotropic receptors often leads to longer-lasting effects and can modulate different ion channel activities over time.</p> Signup and view all the answers

<p>Ionotropic receptors directly open ion channels upon neurotransmitter binding, while metabotropic receptors indirectly influence ion channels through second messenger systems.</p> Signup and view all the answers

<p>Metabotropic receptors are primarily involved in synaptic plasticity due to their role in modulating lasting changes in synaptic strength.</p> Signup and view all the answers

<p>Glial cells can reuptake neurotransmitters and release signals that modulate the activity of both ionotropic and metabotropic receptors, affecting neurotransmission.</p> Signup and view all the answers

<p>G-proteins are activated when neurotransmitters bind to metabotropic receptors, triggering a cascade that produces second messengers, which can modulate ion channel function.</p> Signup and view all the answers

<p>Second messengers like cAMP and cGMP are produced when G-proteins are activated and can alter the conformation of nearby ion channels, affecting cellular functions.</p> Signup and view all the answers

<p>Feedback inhibition refers to the process where autoreceptors inhibit neurotransmitter production from the presynaptic neuron, while heteroreceptors inhibit the production of other neurotransmitters.</p> Signup and view all the answers

<p>The net effect of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) determines whether the neuron reaches the threshold for action potential generation.</p> Signup and view all the answers

<p>Signaling through ionotropic receptors occurs rapidly due to direct ion channel opening, while metabotropic receptor signaling is slower due to its indirect nature involving second messenger systems.</p> Signup and view all the answers

<p>Drugs can target metabotropic receptors at their binding sites, affect second messenger systems, or modify ion channel activity, whereas ionotropic drugs primarily influence the direct opening of ion channels.</p> Signup and view all the answers

<p>Metabotropic receptors change ion channel function indirectly, which can enhance or inhibit neuronal signaling over longer periods, impacting overall brain function and response.</p> Signup and view all the answers

<p>Ionotropic receptors directly control ion channels, allowing rapid changes in membrane potential, while metabotropic receptors activate signaling pathways that result in slower, longer-lasting effects.</p> Signup and view all the answers

<p>Ionotropic glutamate receptors are activated by ligands such as glutamate, causing an influx of Na+ and K+ ions, leading to depolarization.</p> Signup and view all the answers

<p>P2X receptors are activated by ATP and directly facilitate the flow of Na+ and Ca2+ ions, leading to depolarization.</p> Signup and view all the answers

<p>Ligands binding to ionotropic receptors result in immediate ion flow, while those binding to metabotropic receptors trigger a cascade of signaling events that modify cellular activity over time.</p> Signup and view all the answers

<p>Ionotropic receptors mediate fast synaptic transmission, while metabotropic receptors modulate synaptic transmission and influence neuronal plasticity over a more extended period.</p> Signup and view all the answers

<p>The NMDA receptor, a subtype of ionotropic glutamate receptor, is essential for synaptic plasticity and memory function due to its unique properties, including voltage-dependent activation.</p> Signup and view all the answers

<p>Metabotropic receptors are characterized by their association with G-proteins and intracellular signaling pathways rather than direct ion channel activity.</p> Signup and view all the answers

<p>Ionotropic receptors open an ion channel immediately upon activation, while metabotropic receptors initiate a sequence of intracellular signaling events that may involve second messengers.</p> Signup and view all the answers

<p>Ionotropic receptors typically allow the influx of Na+ ions and, depending on the receptor subtype, may also permit Ca2+ ions to enter the neuron.</p> Signup and view all the answers

<p>Ligand binding to metabotropic receptors triggers G-protein activation, which then influences various intracellular signaling cascades, affecting cell function.</p> Signup and view all the answers