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135 Cards in this Set
- Front
- Back
The proper order of a reflex arc is:
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sensory neuron, interneuron, motor neuron
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Which of the following is NOT a factor in determining whether or not two EPSPs combine to reach threshold?
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threshold of the presynaptic cell
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Which of the following is TRUE about EPSPs?
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they decay over time and space
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EPSP
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Excitatory PostSynaptic Potential
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A graded depolarization is known as an?
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excitatory postsynaptic potential
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Which of the following would produce spatial summation?
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present two or more weak stimuli at the same time
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Temporal summation most likely occurs with:
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rapid succession of subthreshold excitation
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A temporary hyperpolarization is known as an?
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IPSP
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Why is the speed of conduction through a reflex arc slower than the speed of conduction of an action potential along an axon?
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Transmissions between neurons at synapses is slower than along axons
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The circuit from sensory neuron to muscle response is called:
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a reflex arc
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In a reflex arc, the coordination between contraction of certain muscles and relaxation of others is mediated by:
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interneurons
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Simultaneous weak stimuli at different locations produce a greater reflexive response than one of the stimuli by itself. What is this phenomenon called?
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spacial summation
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temporal summation is to ____, as spatial summation is to ____.
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time, location
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Which of the following would most likely result in an IPSP?
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chloride ions entering the cell
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To measure temporal summation in single cells, researchers:
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record depolarizations of the postsynaptic neuron
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Even at rest, most neurons have periodic production of action potentials, known as the:
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spontaneous firing rate
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A normal, healthy animal never contracts the flexor muscles and the extensor muscles of the same leg at the same time. Why not?
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when the interneuron sends excitatory messages to one it sends inhibitory messages to the other
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Which of the following is TRUE about the firing rates of neurons?
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EPSPs increase the frequency
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____ are specialized junctions between neurons.
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synapses
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What causes an EPSP?
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the opening of sodium channels
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Which of the following is NOT true about EPSPs?
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they operate on an all-or-one principle
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Which of the following patterns of post-synaptic excitation will most likely result in an action potential?
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rapid sequence of excitatory postsynaptic potentials
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Depolarization is to ____ as hyperpolarization is to ____.
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excitation, inhibitory
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On the basis of what evidence were the properties of synapses first inferred?
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behavioral observations
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What do temporal summation and spatial summation have in common?
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both enable a reflex to occur in response to a weak stimuli
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The primary difference between an EPSP and an action potential is that
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EPSPs are subthreshold events that decay over time and space
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What is the primary difference between temporal summation and spatial summation?
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spacial summation depends on contributions from one than more sensory neuron
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The “decision” for a neuron to fire is determined by the:
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the ratio of EPSPs to IPSPs
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Inhibitory synapses on a neuron:
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hyperpolarize the postsynaptic cell
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A certain weak stimulus produces no reflexive response, but a rapid repetition of that stimulus may produce such a response. What is this phenomenon called?
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temporal summation
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What ordinarily prevents extensor muscles from contracting at the same time as flexor muscles?
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inhibitory synapses in the spinal cord
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In most cases, how many neurotransmitters can activate a postsynaptic neuron?
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several transmitters with different synapses responding to different transmitters
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What is the function of the enzyme acetylcholinesterase?
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it breaks down acetylcholine
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What is the synaptic cleft?
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the gap between the presynaptic and postsynaptic neurons
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Hormones exert their effects:
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similarly to metabotropic neurotransmitters
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Large neurotransmitters (such as peptides) are synthesized in the:
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cell body
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The basic building blocks for the majority of neurotransmitters are:
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amino acids
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____ are a category of chemicals including adenosine and several of its derivatives.
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purines
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The primary method for disposal of peptide neurotransmitters is:
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they diffuse away
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What do dopamine, norepinephrine, and epinephrine share in common?
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they are all synthesized from the same amino acids
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A neurotransmitter receptor is:
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a protein embedded in the membrane
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What happens when a neurotransmitter is released by a presynaptic cell?
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the protein passively spreads across the synaptic cleft
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One of nitric oxide's functions is that it:
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increases blood flow to certain parts of the brain
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A metabotropic synapse, by way of its second messenger:
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can influence in much or all of the postsynaptic cell
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After a meal that was rich in the amino acid tryptophan, which neurotransmitter level would be increased the most?
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serotonin
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The neurotransmitter GABA exerts ____ effects, and its effects are almost always ____.
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ionotropic(affect the strength of contraction of the heart muscle), inhibitory
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"Transporter" proteins transport neurotransmitters:
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back to the presynaptic neuron
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In general, a single neuron releases ____ neurotransmitter(s), and can respond to ____ neurotransmitter(s).
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several, many
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What determines the effect that a neurotransmitter has on the postsynaptic neuron?
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the receptors on the postsynaptic neuron
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Ionotropic effects are characterized by?
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rapid short-lived effects
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A hormone is a chemical that is:
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conveyed by the blood to other organs whose activity it influences
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High concentrations of all neurotransmitters, except for NO, are stored in the:
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presynaptic terminal
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The second messenger communicates to areas:
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within the cell
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After serotonin or one of the catecholamine transmitters stimulates the postsynaptic receptor, most of the transmitter molecules:
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are reabsorbed by the presynaptic cell
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The presynaptic terminal stores high concentrations of neurotransmitter molecules in:
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vesicles
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Receptor molecules for neurotransmitters that exert metabotropic effects are proteins that bind to ____ outside the membrane, and attach to ____ inside the membrane.
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neurotransmitters, G-proteins
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Releasing hormones are synthesized in the ____, and released in the ____.
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hypothalamus, anterior pituitary
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Neurotransmitter is to ____ as cyclic AMP is to ____.
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first messenger, second messenger
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When an action potential reaches the end of an axon, it evokes the release of neurotransmitters by opening ____ channels in the axon terminal.
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calcium
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COMT and MAO are:
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enzymes that convert catecholamines into inactive chemicals
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What is the most unusual thing about the neurotransmitter nitric oxide (NO)?
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It's normally a poisonous gas
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The amino acid tryptophan, is the precursor to?
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serotonin
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A receptor can directly open a channel, exerting an ____ effect or it can produce slower but longer ____ effects.
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ionotropic, metabotropic
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Suppose a new neurotransmitter is identified that does not excite or inhibit postsynaptic cells, but affects the release of other neurotransmitters or the sensitivity of postsynaptic cells. This neurotransmitter would most likely be categorized as a(n):
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neuromodulator
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Although slower than an action potential, synaptic transmission is still relatively fast because:
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the synaptic cleft is very narrow
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Vesicles are located:
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in presynaptic terminals
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Compared to ionotropic effects, metabotropic effects are:
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slower and longer-lasting
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Acetylcholine is synthesized in the:
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presynaptic terminal
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The anterior pituitary is composed of ____, and the posterior pituitary is composed of ____.
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glandular tissue, neural tissue
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A new drug is discovered that affects the activity of enzymes. Which of the following stages of synaptic transmission is most likely to be affected?
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synthesis
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The neuron excretes neurotransmitter through its membrane by a process called:
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exocitosis
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Ionotropic effects:
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may depolarize or hyperpolarize the postsynaptic membrane.
ionotropic: affects the strength of the muscle contractions, especially the heart |
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Reuptake is the absorption of:
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neurotransmitters by the presynaptic membrane
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The main advantage of a neuron releasing more than one neurotransmitter is that:
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it can send more complex messages
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Which of the following actions is most likely to be dependent on ionotropic effects?
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rapid muscle contractions
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All of the following are catecholamines EXCEPT?
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serotonin
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Loewi demonstrated that synapses operate by the release of chemicals. He did this by:
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collecting fluid from a stimulated frog's heart, transferring it to another frog and measuring the heart rate
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If you eat a food containing tryptophan, what can you consume with it to increase its entry to the brain?
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carbohydrates
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Adrenocorticotropic hormone (ACTH) controls:
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secretions of the adrenal cortex
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Which effect is consistently associated with a "second messenger"?
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metabotropic
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What provides the building blocks for synthesizing all neurotransmitters?
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substances found in the diet
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Reuptake is an alternative to which other process?
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enzymatic breakdown of other neurotransmitters
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The correct sequence of chemical events at a synapse is:
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synthesis, transport,release, reuptake
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What would be the effect of a drug that inhibits the action of the enzyme acetylcholinesterase?
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prolonged action of acetylcholine at its synapses
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Given a repetitive series of action potentials in a given neuron, we can expect that:
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many actions potentials will fail to release any neurotransmitters at all
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Nicotine directly stimulates receptors in the central nervous system and at nerve-muscle junctions. These nicotinic receptors are also receptors for which neurotransmitter?
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acetylcholine
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The effect of Ritalin (methylphenidate) on the synapse is most similar to that of:
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cocaine
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The stimulant effects of MDMA are likely due to actions at ____ synapses, while the hallucinogenic effects are likely to due to actions at ____ synapses.
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dopamine, serotonin
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Cannabinoid receptors are located on the:
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the presynaptic neuron
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Our brains respond to plant chemicals because:
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plants use chemicals similar to neurotransmitters
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Which of the following is NOT a likely effect of using marijuana?
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reduced risk of parkinsons
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A drug which produces excitement, alertness, elevated mood, and decreased fatigue is referred to as a:
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stimulant
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Cannabinoid chemicals (such as the active component of marijuana) affect synapses by
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decreasing the release of both glutamate and GABA
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At high doses, MDMA:
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destroys axons that release serotonin
MDMA (ecstasy) |
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A drug that blocks the effects of a neurotransmitter is called a(n):
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antagonist
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A drug that mimics or increases the effects of a neurotransmitter is called a(n):
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agonist
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At the synapse, amphetamine:
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reverses the dopamine transporter
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Why are the withdrawal effects of marijuana usually less intense than other drugs?
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marijuana leaves the body slowly
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Endogenous cannabinoids act to:
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decrease neurotransmitter release from the presynaptic neurons
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At the synapse, cocaine:
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blocks the reuptake of dopamine
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Which drugs most closely resemble the neurotransmitter serotonin?
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hallucinogens
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Which neurotransmitter has been repeatedly connected with addictive drugs?
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dopamine
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What is one factor in determining whether a drug that readily attaches to a receptor will have agonistic or antagonistic effects?
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its efficacy
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Why is marijuana unlikely to interfere with breathing or heart rate?
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receptors for marijuana in those brain areas are absent
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Which effect would be considered to be agonistic?
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stimulating the release of neurotransmitters
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What effect do opiate drugs have on dopamine?
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they indirectly increase the amount of dopamine by blocking the transmitters that usually block dopamine
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Which is MORE characteristic of marijuana users than of cocaine users?
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impairment of attention and memory
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LSD and other hallucinogenic drugs probably exert their effects most directly on what part of the neuron?
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the postsynaptic receptors
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Cannabinoids are a class of chemicals that include:
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marijuana
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To say that a drug has an affinity for a particular type of receptor is to imply that the drug:
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binds to that receptor
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Which effect would be considered to be antagonistic?
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blocking the synthesis of neurotransmitters
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With respect to drug effects, "efficacy" means:
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the degree to which a drug modulates the activity of a receptor
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Anandamide and 2-AG are believed to be the naturally occurring neurotransmitters that bind to the same receptors as which drug?
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marajuana
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A certain drug user experiences intensified sensations and the illusion that time is passing slowly. He also experiences problems with attention and memory. These symptoms are most characteristic of the use of which drug?
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marijuana
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The chemicals used as neurotransmitters in humans are found in:
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apparently all or nearly all other species
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The "key into a lock" analogy best describes:
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a drug's affinity for a receptor
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The presynaptic terminal ordinarily reabsorbs released dopamine through a protein called:
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dopamine transporter
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A drug that relaxes a person and makes them less sensitive to pain is most likely a(n):
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opiate
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If a drug has high affinity and zero efficacy, what effect does it have on the postsynaptic neuron?
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antagonistic
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Why do cocaine and amphetamine produce similar effects?
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both increase the amount of dopamine in the synapses
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Why do the effects of certain transmitters, such as serotonin, vary from one synapse to another?
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there are several types of potsynaptic receptors for serotonin
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If a drug has high affinity and high efficacy, what effect does it have on the postsynaptic neuron?
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agonistic
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Drugs that grossly distort perception are known as:
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hallucinogens
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Autoreceptors monitor the:
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amount of neurotransmitters released
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When opiates block the activity of the locus coeruleus, this results in:
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decreased fear and memory
locus coeruleus "the dark blue spot": a small nucleus in the pons (part of the brain stem) that releases noradrenaline which is a stress horomone |
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Which of the following activities is LEAST likely to stimulate intense dopamine release in the nucleus accumbens?
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running
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The effect of cannabinoids to reduce nausea is most likely mediated by ____ receptors.
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serotonin
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Opiate drugs bind to receptors in the brain for:
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endorphins
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The main difference between methylphenidate (Ritalin), when taken as a medication for attention deficit disorder, and cocaine, when taken as a drug of abuse, is that methylphenidate
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produces the same effects more slowly
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Pert and Snyder's discovery that opiates bind with certain receptors led to what other discovery?
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the endogenous chemicals that bind with those receptors
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The brain area most often linked to drug addiction is the:
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nucleus accumbens
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Methylenedioxymethamphetamine (MDMA) is also known as?
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ecstasy
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common drug to treat alcoholism that produces illness after consuming alcohol is:
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antabuse
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The effectiveness and side-effects of a drug vary from one person to the next. One reason for this is that:
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each drug tends to affect more than one synapse
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Activation of autoreceptors tends to:
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decrease further neurotransmitter release
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