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What role does calcium play in the chemical events at a synapse?
What role does calcium play in the chemical events at a synapse?
Neurotransmitters are synthesized solely in the presynaptic neuron.
Neurotransmitters are synthesized solely in the presynaptic neuron.
False
What happens to neurotransmitter molecules after they separate from their receptors?
What happens to neurotransmitter molecules after they separate from their receptors?
They may be taken back into the presynaptic neuron for recycling or may diffuse away.
The gas known as __________ is considered an odd neurotransmitter because it can be poisonous in large quantities.
The gas known as __________ is considered an odd neurotransmitter because it can be poisonous in large quantities.
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Match the following neurotransmitter types with their synthesis locations:
Match the following neurotransmitter types with their synthesis locations:
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What occurs after action potentials travel down the axon?
What occurs after action potentials travel down the axon?
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All neurons release the same types of neurotransmitters.
All neurons release the same types of neurotransmitters.
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What is the primary function of neurotransmitters at a synapse?
What is the primary function of neurotransmitters at a synapse?
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What happens to neurotransmitters after their signal is terminated?
What happens to neurotransmitters after their signal is terminated?
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Inhibitory neurotransmitters increase the likelihood that a neuron will fire an action potential.
Inhibitory neurotransmitters increase the likelihood that a neuron will fire an action potential.
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Name one example of an excitatory neurotransmitter.
Name one example of an excitatory neurotransmitter.
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_________ neurotransmitters affect a large number of neurons simultaneously and influence the actions of other neurotransmitters.
_________ neurotransmitters affect a large number of neurons simultaneously and influence the actions of other neurotransmitters.
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What role does serotonin primarily serve in the body?
What role does serotonin primarily serve in the body?
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Neurotransmitters are only involved in signaling within a single neuron.
Neurotransmitters are only involved in signaling within a single neuron.
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Match the following neurotransmitters with their type:
Match the following neurotransmitters with their type:
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What is re-uptake in relation to neurotransmitters?
What is re-uptake in relation to neurotransmitters?
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What is a potential effect of a surplus of dopamine?
What is a potential effect of a surplus of dopamine?
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A deficiency of GABA can lead to seizures in the brain.
A deficiency of GABA can lead to seizures in the brain.
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What role does glutamate primarily serve in the brain?
What role does glutamate primarily serve in the brain?
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A lack of dopamine could contribute to feelings of ______.
A lack of dopamine could contribute to feelings of ______.
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What is the consequence of excessive glutamate in the body?
What is the consequence of excessive glutamate in the body?
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Match the following neurotransmitters with their primary effects:
Match the following neurotransmitters with their primary effects:
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Overproduction of GABA can cause insomnia.
Overproduction of GABA can cause insomnia.
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Peptides are defined as short chains of ______ amino acids.
Peptides are defined as short chains of ______ amino acids.
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What is the primary effect of antipsychotic medications on dopamine receptors?
What is the primary effect of antipsychotic medications on dopamine receptors?
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Heroin binds to opioid receptors, leading to a release of low levels of dopamine.
Heroin binds to opioid receptors, leading to a release of low levels of dopamine.
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What effect does cocaine have on the central nervous system?
What effect does cocaine have on the central nervous system?
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Marijuana contains the psychoactive chemical __________, which interacts with cannabinoid receptors.
Marijuana contains the psychoactive chemical __________, which interacts with cannabinoid receptors.
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Match the following drugs with their primary action:
Match the following drugs with their primary action:
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What is the main characteristic of myasthenia gravis?
What is the main characteristic of myasthenia gravis?
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Huntington’s disease can be cured with medication.
Huntington’s disease can be cured with medication.
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What neurotransmitter is primarily involved in the synaptic transmission impairment in myasthenia gravis?
What neurotransmitter is primarily involved in the synaptic transmission impairment in myasthenia gravis?
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An imbalance of __________ can contribute to conditions of anxiety.
An imbalance of __________ can contribute to conditions of anxiety.
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Match the following disorders with their associated neurotransmitter:
Match the following disorders with their associated neurotransmitter:
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What is the role of SSRIs in treating depression?
What is the role of SSRIs in treating depression?
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Benzodiazepines help to increase nerve signal excitability in the brain.
Benzodiazepines help to increase nerve signal excitability in the brain.
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Identify one psychological condition treated with SSRIs.
Identify one psychological condition treated with SSRIs.
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Study Notes
Sequence of Chemical Events at a Synapse
- Neurotransmitter Synthesis: Neurons produce neurotransmitters, smaller ones in axon terminals and neuropeptides in the cell body.
- Action Potential and Calcium Release: Action potentials travel down the axon, triggering calcium influx at the presynaptic terminal. Calcium release neurotransmitters into the synaptic cleft.
- Neurotransmitter Binding and Postsynaptic Neuron Activation: Neurotransmitters diffuse across the synaptic cleft, bind to receptors, and alter the activity of the postsynaptic neuron.
- Neurotransmitter Separation from Receptors: Neurotransmitters detach from their receptors.
- Neurotransmitter Removal: Neurotransmitters are either re-uptaked by the presynaptic neuron for recycling or diffuse away.
- Postsynaptic Feedback: Some postsynaptic cells send signals back to the presynaptic cell to regulate further neurotransmitter release.
Neurotransmitters
- Nitric Oxide (NO): An unusual gas neurotransmitter, released by many local neurons. It's poisonous in large quantities but efficiently produced by neurons.
- Signal Termination: After neurotransmission, the signal is terminated by enzyme breakdown, diffusion, or re-uptake.
- Re-uptake: Neurotransmitters are reabsorbed back into the presynaptic neuron, either stored for future use or broken down by enzymes.
Neurotransmitter Classification
- Excitatory Neurotransmitters: Increase the likelihood of a neuron firing an action potential (e.g., epinephrine, norepinephrine)
- Inhibitory Neurotransmitters: Decrease the likelihood of a neuron firing an action potential (e.g., GABA, endorphins)
- Modulatory Neurotransmitters (Neuromodulators): Affect multiple neurons, influencing the effects of other neurotransmitters (e.g., serotonin, dopamine)
Monoamines
- Serotonin: Crucial for mood regulation, affecting happiness, anxiety, appetite, pain control, and sleep cycles.
- Dopamine: Involved in decision-making, emotional response, reward, motivation, and motor control. Excess dopamine can lead to aggression, impulsivity, and addiction. Deficiencies are linked to depression and Parkinson's disease.
Amino Acids
- GABA (Gamma-aminobutyric Acid): Regulates anxiety, vision, and motor control. Insufficient GABA can lead to poor impulse control and seizures. Excess can cause hypersomnia and fatigue.
- Glutamate: Essential for cognitive functions like memory and learning. The most abundant neurotransmitter in the central nervous system. Overactivation causes excitotoxicity (neuron death), potentially contributing to Alzheimer's, stroke, and epilepsy. Insufficient glutamate can lead to psychosis, insomnia, and concentration problems.
Peptides
- Peptides: Short chains of amino acids with various biological functions. They can act as hormones affecting other parts of the body.
Huntington's Disease
- GABA Levels: A chronic reduction of GABA in the brain is linked to Huntington's disease. The exact mechanisms are complex.
- Treatment: While Huntington's is inherited, symptoms can be managed by pharmacologically increasing inhibitory neurotransmitters.
Disorders Associated with Defects in Neurotransmission
- Myasthenia Gravis: An autoimmune disease affecting neuromuscular junctions. Antibodies block acetylcholine receptors, impairing muscle function. This is typically caused by autoimmune responses but can be genetically inherited.
- Anxiety: May involve reduced GABA activity, potentially due to imbalances in GABA receptor inhibitors, stimulators, or both. Imbalances in norepinephrine and serotonin responses may also play a role.
- Seizure Disorders: Characterized by sudden bursts of synchronized neuron firing, possibly due to increased glutamate activity or reduced GABA activity.
Medications
- SSRIs (Selective Serotonin Reuptake Inhibitors): Block serotonin reuptake, elevating serotonin levels in the synaptic cleft. Used for depression, anxiety, PTSD, panic disorder, OCD, and phobias.
- Benzodiazepines: Enhance GABA's effect in the brain, producing a calming effect. Prescribed for insomnia, anxiety, panic disorder, and epilepsy. Typically used short-term because of potential side effects.
- Antipsychotic Medications: Antagonize dopamine receptors, reducing dopamine activity. Used for schizophrenia, dementia, bipolar disorder, and major depression.
Illicit Drugs
- Marijuana (THC): Binds to cannabinoid receptors, inducing relaxation and increasing dopamine levels.
- Heroin: Binds to opioid receptors, triggering massive dopamine release. Tolerance develops with repeated use.
- Cocaine: Stimulant drug that increases dopamine levels, leading to alertness, energy, and euphoria. Effects are short-lived and can lead to irritability, depression, and cravings.
- Ecstasy (MDMA): Stimulant and hallucinogenic drug. Affects serotonin, dopamine, and norepinephrine levels.
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Description
Explore the critical sequence of chemical events at a synapse, from neurotransmitter synthesis to their removal. This quiz delves into neuron communication and the roles of various neurotransmitters, emphasizing essential concepts in neurobiology.
