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57 Cards in this Set
- Front
- Back
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What is a synapse?
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The gap between two neurons where a specialized type of communication occurs.
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What type of communication occurs in a synapse?
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Neurotransmitters get released.
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What did Charles Sherrington infer?
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That there is communication between the neurons. This is because reflexes are slower than the speed of transmission along the neuron, meaning there must be a delay at the synapse.
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What are the two ways that synapses can sum stimulation?
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1. 1 Neuron can fire several times.
2. Multiple neurons all fire at once. |
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What is a reflex arc?
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The total amount of time from stimulation to reflex.
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Are neurotransmitters go/no go like action potentials?
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No.
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What is Excitatory Postsynaptic Potential?
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EPSP. A neurotransmitter that triggers and influx of sodium (+) into the receiving neuron.
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What is Inhibitory Postsynaptic Potential?
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IPSP. A neurotransmitter that hyperpolarizes the cell, either by stimulating the release of potassium (+) or an influx of chloride (-).
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What type of potential do single neurons create?
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Graded potential.
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What are the two ways that a neuron gets enough input to fire?
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1. Temporal summation
2. Spatial summation. |
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What is temporal summation?
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Occurs when one presynaptic fires repeatedly until the next neuron gets enough input to fire.
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What is spatial summation?
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Occurs when several presynaptics fire simultaneously until the next neuron gets enough input to fire.
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What research did Otto Loewi do?
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He stimulated the vagus nerves of frog to slow the heart. By extracting fluid from that frog's heart and injecting it into the next, the second frog's heart slowed as well. This proved that synaptic communication is chemical.
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How was it discovered that synaptic communication is chemical?
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Otto Loewi's frog experiment.
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Where does the synthesis of small neurotransmitters occur?
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These are made in the terminals.
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What is the chemical sequence of communication?
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1. Neurotransmitters are synthesized.
2. The action potential opens channels that pull in calcium (+), which push the neurotransmitters out of the gap. 3. Released molecules attach to receptors in the dendrites of the next neuron. |
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Where are large neurotransmitters synthesized?
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They are made in the neuron, then transported.
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What is reuptake?
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When things are returned to the presynaptic neuron.
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What are the three types of reputake?
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1. Molecules can be released from the receptor sites, usually as inactive chemicals. They are then eaten by astrocytes. (Reduce).
2. If the neurotransmitter was sent by some protein carrier, then now-empty vesicle can re-enter the pre-synaptic neuron (Reuse). 3. Transporter proteins return unused neurotransmitters to the original neuron (Recycle). |
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What are most popular drugs now considered?
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Reuptake inhibitors.
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What is exocytosis?
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Releasing of the neurotransmitter into the cleft.
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How long does exocytosis usually take?
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1-2 milliseconds.
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In what two ways does the amount of neurotransmitter released vary?
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1. There is variability in the amount of neurotransmitter stored in each cell. The cell always fires at the same strength, but the amount of NT released varies. Can be none to a lot.
2. It also varies from synapse to synapse. |
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How are neurotransmitters stored and released?
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Neurotransmitters are stored individually in vesicles, and are released in the same way.
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What are the two types of effects that neurotransmitters can produce?
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1. Ionotropic
2. Metabotropic |
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What are ionotropic effects?
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Binding of the neurotransmitter produces a nearly instantaneous signal to open the gates for some ion.
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What is the typical time of activation and duration for ionotropic binding?
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10 ms for activation and 20 ms for duration.
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What is the most common excitatory transmitter?
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Glutamate
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What does glutamate do?
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....
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What is the most common inhibatory transmitter?
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GABA
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What is GABA?
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....
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What is metabotropic binding?
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Rather than activating ion channels, neurotransmitters sometimes initiate a series of metabolic reactions.
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What is the activation and duration of metabotropic binding?
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activate within 30 ms or longer and can last for days.
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Which type of binding lasts longer?
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Metabotropic.
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What is the first messenger of metabotropic binding?
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Neurotransmitters instruct the protein inside the neuron to bend, so that it chemically interacts with other molecules.
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What is the secondary messenger of the metabotropic binding?
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Delivers signals to other areas of the cell to change metabolic processes. This can include opening ion channels, altering protein production, or can activate a portion of the chromosome (puberty).
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What are neurotransmitters?
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Chemicals released by one neuron that affect another.
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What are the two main types of neurotransmitters?
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Amino acids and Monoamines.
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What are the five most common amino acids?
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1. Glutamate
2. GABA 3. Glycine 4. Aspartame 5. Tryptophan |
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What is the structure of increasingly complex amino acids?
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amino acids -> peptides -> polypeptides -> proteins.
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What are the 3 most common peptides?
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1. Endorphins
2. Substance P 3. Nueropeptide Y |
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What does Substance P do?
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Blocks acute pain.
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What is acetycholine and what does it do?
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It is a modified amino acid and it controls voluntary motion.
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What are monoamines?
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Non-acidic modified amino acids.
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What are the 4 most common amino acids?
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1. Serotonin
2. Dopamine 3. Epinephrine 4. Norepinephrine |
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What does serotonin do?
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Controls lots of functions, including sleep and euphoria.
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What does dopamine do?
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Happy happy joy joy
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What do epinephrine and norepinephrine do? What is their other name?
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Also referred to as adrenaline and noradrenaline.
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How does turkey make you tired?
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Tryptophan is an amino acid found in turkey. When consuming carbs, insulin strips away the other amino acids from the proteins, leaving only tryptophan. This is sent straight to the brain where it can cross the blood-brain barrier without competition. Tryptophan promotes the production of serotonin, which makes you sleepy.
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What are endogenous chemicals?
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Naturally occuring chemicals in the body.
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What are exogenous chemicals?
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Chemicals introduced from outside the body that either mimic specific neurotransmitters or alter the body's production rate.
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Do exogenous chemicals affect the endogenous chemicals?
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Yes, there is a complex series of effects on endogenous chemicals.
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Where do drugs that affect behavior do their work?
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At the synapse. Most mess with the body's normal communication.
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What is an antagonist?
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A drug that blocks the effect of a neurotransmitter. This is needed when the body is producing too much of something on its own.
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What is an agonist?
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A drug that mimics or increases the effects of a neurotransmitter. This is needed when the body is not producing enough of something on its own.
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What are the four main drug effects?
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1. Increases or decreases neurotransmitter production.
2. Cases it to leak from the vesicles. 3. Increases release, decreases reuptake. 4. Stimulates or blocks the postsynaptic terminals. |
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What are the two reasons that drugs have side effects?
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1. Synapses respond to particular types of chemicals. They will also respond to similar shapes.
2. Most neurotransmitters (and drugs) will activate receptors on several different kinds of neurons. This means that all 12 receptors for serotonin will be affected. |
