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Questions and Answers
Which neurotransmitter is primarily responsible for inhibitory signaling in the central nervous system?
Which neurotransmitter is primarily responsible for inhibitory signaling in the central nervous system?
- Aspartate
- Glutamate
- Acetylcholine
- Glycine (correct)
What is the primary excitatory neurotransmitter in the central nervous system?
What is the primary excitatory neurotransmitter in the central nervous system?
- Serotonin
- Glycine
- GABA
- Glutamate (correct)
Which category of neurotransmitters does GABA belong to?
Which category of neurotransmitters does GABA belong to?
- Peptides
- Trace Amines
- Purines
- Amino Acids (correct)
Which neurotransmitter category includes molecules like serotonin and dopamine?
Which neurotransmitter category includes molecules like serotonin and dopamine?
What role does aspartate play in neurotransmission?
What role does aspartate play in neurotransmission?
What occurs when there is an action potential in a neuron?
What occurs when there is an action potential in a neuron?
What type of ion is associated with excitatory synapses?
What type of ion is associated with excitatory synapses?
What triggers the opening of voltage-gated sodium channels?
What triggers the opening of voltage-gated sodium channels?
Which neurotransmitter is primarily associated with inhibitory synapses?
Which neurotransmitter is primarily associated with inhibitory synapses?
What happens when ligand-gated sodium channels are activated?
What happens when ligand-gated sodium channels are activated?
What is the primary function of the synaptic terminal?
What is the primary function of the synaptic terminal?
Which of the following statements accurately describes dendrites?
Which of the following statements accurately describes dendrites?
Which neurotransmitter is primarily associated with excitatory postsynaptic potentials in the CNS?
Which neurotransmitter is primarily associated with excitatory postsynaptic potentials in the CNS?
What describes the process by which an action potential is generated in neurons?
What describes the process by which an action potential is generated in neurons?
Which component is primarily responsible for transmitting action potentials to other cells?
Which component is primarily responsible for transmitting action potentials to other cells?
What is the primary role of neurotransmitters?
What is the primary role of neurotransmitters?
What is the relationship between the synaptic cleft and synaptic transmission?
What is the relationship between the synaptic cleft and synaptic transmission?
Which of the following statements about synaptic vesicles is correct?
Which of the following statements about synaptic vesicles is correct?
What initiates an action potential in the post-synaptic cell?
What initiates an action potential in the post-synaptic cell?
For another action potential to be generated after an initial one, what is required?
For another action potential to be generated after an initial one, what is required?
What type of ion channels must be activated to generate another action potential?
What type of ion channels must be activated to generate another action potential?
What results from the summation at the synaptic connections to the postsynaptic cell?
What results from the summation at the synaptic connections to the postsynaptic cell?
What role do dendrites play in relation to action potentials?
What role do dendrites play in relation to action potentials?
Which of the following ions primarily facilitates the creation of an action potential?
Which of the following ions primarily facilitates the creation of an action potential?
What is the primary effect of positively charged ions influx on the neuron?
What is the primary effect of positively charged ions influx on the neuron?
Which statement about action potentials is accurate?
Which statement about action potentials is accurate?
What is the threshold membrane potential necessary to generate an action potential?
What is the threshold membrane potential necessary to generate an action potential?
Which process occurs immediately after depolarization reaches the threshold?
Which process occurs immediately after depolarization reaches the threshold?
What is the main role of inhibitory postsynaptic potentials (IPSPs) in neuronal activity?
What is the main role of inhibitory postsynaptic potentials (IPSPs) in neuronal activity?
What triggers the opening of voltage-gated sodium channels during the action potential initiation?
What triggers the opening of voltage-gated sodium channels during the action potential initiation?
During the repolarization phase of an action potential, which ion primarily leaves the neuron?
During the repolarization phase of an action potential, which ion primarily leaves the neuron?
What happens to the inactivation gate of sodium channels once the action potential is generated?
What happens to the inactivation gate of sodium channels once the action potential is generated?
What is the primary function of the Na+/K+ pump in the context of action potentials?
What is the primary function of the Na+/K+ pump in the context of action potentials?
Which ion does NOT have an inactivation gate during action potential changes?
Which ion does NOT have an inactivation gate during action potential changes?
What occurs during hyperpolarization of a neuron?
What occurs during hyperpolarization of a neuron?
Which of the following statements about action potentials is correct?
Which of the following statements about action potentials is correct?
What is the resting membrane potential of a typical neuron?
What is the resting membrane potential of a typical neuron?
What primarily drives the movement of sodium ions into the neuron during depolarization?
What primarily drives the movement of sodium ions into the neuron during depolarization?
Which of the following best describes the state of voltage-gated sodium channels during repolarization?
Which of the following best describes the state of voltage-gated sodium channels during repolarization?
What is the effect of EPSPs on a neuron's membrane potential?
What is the effect of EPSPs on a neuron's membrane potential?
What term describes the diffusion of positively charged sodium ions into a postsynaptic cell?
What term describes the diffusion of positively charged sodium ions into a postsynaptic cell?
Which of the following statements is true regarding synapses on the soma compared to those on dendrites?
Which of the following statements is true regarding synapses on the soma compared to those on dendrites?
What triggers the opening of voltage-gated sodium channels in the context of postsynaptic responses?
What triggers the opening of voltage-gated sodium channels in the context of postsynaptic responses?
Which of the following best describes the impact of local excitatory postsynaptic potentials (ePSPs) on neuronal activity?
Which of the following best describes the impact of local excitatory postsynaptic potentials (ePSPs) on neuronal activity?
In which phase of neuronal transmission do voltage-gated sodium channels primarily play a pivotal role?
In which phase of neuronal transmission do voltage-gated sodium channels primarily play a pivotal role?
What happens to potassium ions when potassium channels open in a neuron?
What happens to potassium ions when potassium channels open in a neuron?
What is the primary factor that influences the movement of ions across the membrane?
What is the primary factor that influences the movement of ions across the membrane?
Which of the following statements accurately describes the relationship between electrical potential and ion movement?
Which of the following statements accurately describes the relationship between electrical potential and ion movement?
How does the membrane potential change when potassium ions leave the cell?
How does the membrane potential change when potassium ions leave the cell?
What occurs when there is a decreased potential difference across the membrane?
What occurs when there is a decreased potential difference across the membrane?
What is the primary reason that the resting membrane potential is measured as a negative value?
What is the primary reason that the resting membrane potential is measured as a negative value?
Which of the following describe gaseous neurotransmitters?
Which of the following describe gaseous neurotransmitters?
How are neurotransmitter precursors made available for synthesis in neurons?
How are neurotransmitter precursors made available for synthesis in neurons?
What is the typical resting potential value of a neuron?
What is the typical resting potential value of a neuron?
Which neurotransmitter is considered a trace amine?
Which neurotransmitter is considered a trace amine?
What primarily affects the difference in charge across a neuron's membrane at rest?
What primarily affects the difference in charge across a neuron's membrane at rest?
Where are the enzymes necessary for neurotransmitter synthesis typically produced?
Where are the enzymes necessary for neurotransmitter synthesis typically produced?
Which gas is not considered a gaseous neurotransmitter?
Which gas is not considered a gaseous neurotransmitter?
What is the primary function of autoreceptors in neuronal communication?
What is the primary function of autoreceptors in neuronal communication?
How are neurotransmitters typically removed from the synaptic cleft?
How are neurotransmitters typically removed from the synaptic cleft?
What mechanism do transporter proteins utilize to move neurotransmitters across the presynaptic membrane?
What mechanism do transporter proteins utilize to move neurotransmitters across the presynaptic membrane?
What role do glial cells play in neurotransmitter management?
What role do glial cells play in neurotransmitter management?
Which statement about neurotransmitter degradation is accurate?
Which statement about neurotransmitter degradation is accurate?
What is a common misbelief about the transporters of neurotransmitters?
What is a common misbelief about the transporters of neurotransmitters?
What may occur if neurotransmitter reuptake is impaired?
What may occur if neurotransmitter reuptake is impaired?
What is not a method used to deactivate neurotransmitters in the synaptic cleft?
What is not a method used to deactivate neurotransmitters in the synaptic cleft?
What is the result of the influx of negatively charged chloride ions in the postsynaptic cell?
What is the result of the influx of negatively charged chloride ions in the postsynaptic cell?
What prevents voltage-gated sodium ion channels from opening in the postsynaptic cell?
What prevents voltage-gated sodium ion channels from opening in the postsynaptic cell?
What phenomenon describes the summation of multiple synaptic events required to reach action potential threshold?
What phenomenon describes the summation of multiple synaptic events required to reach action potential threshold?
What must occur for a postsynaptic neuron to generate an action potential after receiving excitatory input?
What must occur for a postsynaptic neuron to generate an action potential after receiving excitatory input?
How is an inhibitory postsynaptic potential (IPSP) characterized in terms of membrane potential?
How is an inhibitory postsynaptic potential (IPSP) characterized in terms of membrane potential?
Which action describes what occurs during synaptic transmission in relation to a presynaptic neuron?
Which action describes what occurs during synaptic transmission in relation to a presynaptic neuron?
Which factors influence the likelihood of postsynaptic action potential initiation?
Which factors influence the likelihood of postsynaptic action potential initiation?
What is the effect of the postsynaptic cell receiving insufficient excitatory signals?
What is the effect of the postsynaptic cell receiving insufficient excitatory signals?
How can multiple simultaneous presynaptic neuron activations impact a postsynaptic neuron?
How can multiple simultaneous presynaptic neuron activations impact a postsynaptic neuron?
What role do ligand-gated chloride channels play during neurotransmission?
What role do ligand-gated chloride channels play during neurotransmission?
What is the significance of the summation of synaptic events in the context of action potentials?
What is the significance of the summation of synaptic events in the context of action potentials?
What buffering mechanism exists to prevent excessive action potential generation in the postsynaptic cell?
What buffering mechanism exists to prevent excessive action potential generation in the postsynaptic cell?
What occurs when a single excitatory postsynaptic potential (ePSP) is insufficient?
What occurs when a single excitatory postsynaptic potential (ePSP) is insufficient?
Which condition must be met for a postsynaptic neuron's action potential to be considered likely?
Which condition must be met for a postsynaptic neuron's action potential to be considered likely?
Study Notes
Gaseous Neurotransmitters
- Gaseous neurotransmitters are unique because they are not stored in synaptic vesicles and are produced on demand.
- Examples of gaseous neurotransmitters include Nitric Oxide (NO), Carbon Monoxide (CO), and Hydrogen Sulphide (H2S).
Trace Amines
- Trace amines are related to classic monoamines but are found in the brain at much lower levels.
- Examples of trace amines include Beta-phenylethylamine (PEA), Tyramine, Tryptamine, and Octopamine.
Neurotransmitter Synthesis
- Neurotransmitters are synthesized locally within the axon terminal.
- Precursors necessary for synthesis are either taken up by selective transporters on the membrane of the terminal or readily available byproducts of cellular processes that take place within the neuron itself.
- Enzymes for synthesizing neurotransmitters are usually produced in the cell body and transported to the terminal by slow axonal transport.
The Membrane Potential
- The resting potential is measured as a negative value because of the higher concentration of negatively charged ions (anions) inside the cell.
- The membrane potential measures the difference in charges between the inside of the cell and the outside.
- At rest, the inside of the cell is much more negatively charged than the outside, around -70mV, although this value varies between neurons.
The Resting Potential
- The resting potential refers to the membrane potential when the cell is at rest.
- The difference in voltage inside compared to outside is -70mv (this is called potential difference).
- This difference is due to the concentration of anions (like organic anions and PO4) inside the cell and a higher concentration of Sodium ions outside the cell.
The Resting Potential
- Positively charged ions are attracted to the side of the membrane with a more negative electrical potential.
- Ion concentration gradients and ion charge gradients create an electrochemical gradient across the membrane.
- This electrochemical gradient contributes to the membrane potential.
Membrane Potential and Ion Movement
- The potential difference across the membrane can be influenced by the opening and closing of ion channels.
- Opening potassium channels will increase the membrane potential (making it more negative), as potassium ions will leave the cell, decreasing the positive charge inside the cell.
Autoreceptor
- Autoreceptors are sensitive to higher concentrations of the same neurotransmitter.
Neurotransmitter Deactivation
- The action of neurotransmitters must be terminated after release.
- There are several mechanisms for neurotransmitter deactivation:
- Taken up by the presynaptic neuron via a transporter protein
- Inactivated/degraded by enzymes in the synaptic cleft
- Taken up by glial cells
- Diffuses away into the periphery.
Neurotransmitter Reuptake
- Specific transporter proteins remove most small-molecule neurotransmitters (or their metabolites) from the synaptic cleft, delivering them back to the presynaptic terminal for reuse.
- These transporters are highly specific.
- Reuptake also occurs at glial cells.
Neurotransmitter Reuptake Mechanism
- Transporters usually utilize symport to transport neurotransmitters across the membrane of the presynaptic neuron.
- The neurotransmitter binds to sodium ions, and sodium ions flow down their concentration and electrical gradient, pulling the neurotransmitter into the cell against its own gradient.
Neurotransmitter Degradation
- After a neurotransmitter has been secreted into the synaptic cleft, it must be removed to enable the postsynaptic cell to produce another synaptic event.
- Neurotransmitters can undergo degradation by specific enzymes.
Excitatory Postsynaptic Potential (EPSP)
- The influx of positively charged sodium ions into the postsynaptic cell is called an excitatory postsynaptic potential.
- These ions can spread through the soma.
- Synapses on the soma have a larger effect than those on dendrites.
Inhibitory Postsynaptic Potential (IPSP)
- The influx of negatively charged chloride ions into the postsynaptic cell is called an inhibitory postsynaptic potential.
- These ions cause a more negative membrane potential, preventing voltage-gated sodium ion channels from opening.
- This can prevent an action potential from being initiated in the postsynaptic cell.
Summation
- A single EPSP is usually unable to bring a postsynaptic neuron to the action potential threshold.
- Postsynaptic responses result from the summation of many synaptic events from many incoming neurons.
- The probability of initiating an action potential is higher when multiple presynaptic neurons are firing action potentials simultaneously.
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Test your knowledge on neurotransmitters with this quiz! Explore questions related to inhibitory and excitatory neurotransmitters, and their respective categories. Discover the roles of molecules like GABA, serotonin, and dopamine in neurotransmission.
