Podcast
Questions and Answers
During the repolarization phase of an action potential, which of the following events primarily contributes to the neuron's membrane potential becoming more negative?
During the repolarization phase of an action potential, which of the following events primarily contributes to the neuron's membrane potential becoming more negative?
- Efflux of potassium ions (K+) out of the neuron. (correct)
- Influx of chloride ions (Cl-) into the neuron.
- Influx of sodium ions (Na+) into the neuron.
- Closure of potassium (K+) channels.
If a toxin selectively blocked voltage-gated sodium channels in a neuron, what effect would this have on the neuron's ability to generate action potentials?
If a toxin selectively blocked voltage-gated sodium channels in a neuron, what effect would this have on the neuron's ability to generate action potentials?
- The neuron would be unable to depolarize to reach threshold. (correct)
- The neuron would still be able to depolarize fully, but repolarization would be impaired.
- The neuron would fire action potentials more frequently.
- The neuron would hyperpolarize more readily.
Which of the following best describes the role of the sodium-potassium (Na+/K+) pump in maintaining the resting membrane potential of a neuron?
Which of the following best describes the role of the sodium-potassium (Na+/K+) pump in maintaining the resting membrane potential of a neuron?
- It is primarily responsible for the rapid depolarization during an action potential.
- It allows Na+ and K+ ions to passively diffuse across the membrane down their concentration gradients.
- It actively transports Na+ out of the neuron and K+ into the neuron, against their concentration gradients. (correct)
- It actively transports Na+ into the neuron and K+ out of the neuron, against their concentration gradients.
Which mechanism primarily clears neurotransmitters from the synaptic cleft, involving their reabsorption back into the presynaptic neuron?
Which mechanism primarily clears neurotransmitters from the synaptic cleft, involving their reabsorption back into the presynaptic neuron?
What would be the most likely effect of a drug that inhibits the enzyme responsible for degrading acetylcholine (ACh) in the synapse?
What would be the most likely effect of a drug that inhibits the enzyme responsible for degrading acetylcholine (ACh) in the synapse?
Which of the following statements accurately describes the role of NMDA receptors in synaptic plasticity?
Which of the following statements accurately describes the role of NMDA receptors in synaptic plasticity?
If a researcher discovers a new drug that selectively enhances the activity of GABA receptors, which of the following effects would be most likely?
If a researcher discovers a new drug that selectively enhances the activity of GABA receptors, which of the following effects would be most likely?
A person experiencing a deficiency in dopamine production might exhibit symptoms related to which functions?
A person experiencing a deficiency in dopamine production might exhibit symptoms related to which functions?
How does curare, a toxin that blocks nicotinic acetylcholine receptors, affect muscle function?
How does curare, a toxin that blocks nicotinic acetylcholine receptors, affect muscle function?
Which neurotransmitter system is most directly associated with the rewarding effects of opioid drugs?
Which neurotransmitter system is most directly associated with the rewarding effects of opioid drugs?
Flashcards
Action potential
Action potential
An electrical signal that travels along a neuron to transmit information.
Resting potential
Resting potential
The voltage inside a neuron when it is not actively transmitting signals, typically around -70mV.
Depolarization
Depolarization
The process where the inside of a neuron becomes more positive due to influx of Na+ ions.
Repolarization
Repolarization
Signup and view all the flashcards
Hyperpolarization
Hyperpolarization
Signup and view all the flashcards
Neurotransmitters
Neurotransmitters
Signup and view all the flashcards
Vesicles
Vesicles
Signup and view all the flashcards
Receptors
Receptors
Signup and view all the flashcards
Transporters
Transporters
Signup and view all the flashcards
Glutamate
Glutamate
Signup and view all the flashcards
Study Notes
Action Potential
- Electrical signal that travels along a neuron, transmitting information.
- Resting potential is -70mV, meaning the inside of the neuron is negatively charged relative to the outside.
Steps of Action Potential
- Depolarization Begins: Sodium channels open, and Na+ ions rush into the neuron, making the inside more positive.
- Full Depolarization: The neuron reaches a threshold of approximately -55mV, resulting in more Na+ channels opening and a rapid increase in voltage to +30mV.
- Repolarization Begins: K+ channels open, and K+ ions exit the neuron, making the inside more negative.
- Peak & Na+ Channels Close: Na+ channels close at peak voltage to prevent further sodium influx.
- Hyperpolarization (Refractory Period): K+ continues to exit, causing the neuron to become more negative than the resting potential, about -80mV; during this period, the neuron cannot immediately fire another action potential.
- Restoration of Resting Potential: The Na+/K+ pump actively transports Na+ out and K+ back into the neuron, returning it to its resting potential of -70mV.
Neuron & Synapse
- Key parts include Neurotransmitters, Vesicles, Receptors, Post-synaptic neuron (dendrite), Pre-synaptic neuron (axon terminal), Transporter, and Synapse.
Neurotransmitter Release Process
- Calcium (Ca2+) enters the axon terminal upon arrival of an action potential.
- Neurotransmitters are released from vesicles into the synapse.
- Neurotransmitters bind to receptors on the post-synaptic neuron
- Neurotransmitters are removed from the synapse through:
- Reuptake: Transporters recycle neurotransmitters back into the pre-synaptic neuron.
- Enzymatic Degradation: Enzymes break down neurotransmitters in the synaptic cleft.
- Diffusion: Neurotransmitters drift away from the synapse over time.
Neurotransmitters & Their Functions
- Glutamate
- Primary excitatory neurotransmitter.
- Depolarizes post-synaptic neurons.
- Receptors include AMPA and NMDA receptors.
- AMPA Receptors: Fast-acting and cause immediate depolarization by allowing Na+ to enter the post-synaptic neuron.
- NMDA Receptors: Slower-acting and require both glutamate binding and membrane depolarization to remove a magnesium (Mg2+) block; allow calcium (Ca2+) influx, strengthening synaptic connections and crucial for learning and memory.
- GABA (Gamma-Aminobutyric Acid)
- Main inhibitory neurotransmitter.
- Hyperpolarizes post-synaptic neurons to reduce activity.
- Acetylcholine (ACh)
- Enables muscle contraction and cognitive functions.
- Receptors include Nicotinic and Muscarinic.
- Nicotinic Receptors: Ionotropic (fast-acting), found in muscles and the brain.
- Muscarinic Receptors: Metabotropic (slower-acting), found in the brain and heart.
- Curare blocks nicotinic receptors, leading to paralysis.
- Dopamine (DA)
- Involved in movement and motivation.
- Produced in the substantia nigra & ventral tegmental area (VTA).
- Key for "wanting" (not pleasure itself), increasing during unexpected rewards & reward cues.
- Norepinephrine (NE)
- Regulates attention, arousal, and the fight-or-flight response.
- Structurally similar to dopamine.
- Oxytocin
- Promotes social bonding, trust, and pair bonding (high levels in prairie voles!).
- Serotonin
- Regulates mood, sleep, and hunger.
- Produced in the Raphe Nucleus.
- Opioids
- Involved in pain relief and pleasure.
- Endorphin: Mu receptor (pain relief, euphoria)
- Enkephalin: Delta receptor (analgesia, mood regulation)
- Dynorphin: Kappa receptor (pain modulation, stress response)
- Involved in pain relief and pleasure.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
