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34 Cards in this Set
- Front
- Back
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In the sympathetic nervous system are the preganglionic fibers short or long?
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Short
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In the sympathetic nervous system are the postganglionic fibers short or long?
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Long
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In the parasympathetic nervous system are the preganglionic fibers short or long?
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Long
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In the parasympathetic nervous system are the postganglionic fibers short or long?
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Short
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The postganglionic fiber of the parasympathetic nerve terminal releases Ach except in what?
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Erectile tissue of genitalia, releases nitric oxide
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In the sympathetic neuroeffector junctions, norepinephrine is the neurotransmitter except in what?
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Sweat glands in humans, releases Ach
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What class of drugs can act either by directly stimulating adrenergic receptors or indirectly by release of catecholamines from adrenergic neurons?
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Adrenergic agonists or sympathomimetics
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What is the rate limiting step in synthesis of nor-epinephrine?
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Tyrosine being hydroxylated to DOPA
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What converts dopamine to nor-epinephrine?
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Dopamine B hydroxylase enzyme
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What causes vesicles of nor-epinephrine in the cytoplasm of the neuron to be released by exocytosis?
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Influx of Ca+ ions
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Is there active reuptake of free norepinephrine back into the axon terminal?
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Yes
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Both Sides
How many different receptor classifications are there for adrenergic receptors? |
alpha1
alpha2 beta1 beta2 beta3 |
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Which type of receptor is located on the post synaptic membrane of the effector organ?
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Alpha 1
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Which receptor is activated through G-protein activation of phopholipase C?
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Alpha 1
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Which type of receptor is primarily located on pre-synaptic nerve endings and also postsynaptically on beta cells of pancreas?
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Alpha 2
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When alpha2 receptors are stimulated what happens?
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Causes feedback inhibition of release of norepinephrine
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What is the rank order of potency for alpha receptors?
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Epinephrine
Norepinephrine Isoproterenol |
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What type of receptors are present in the heart, juxta glomerular apparatus of kidney and fat cells and have equal affinities for epinephrine and norepinephrine?
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Beta 1
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What type of receptors are present in the blood vessels of skeletal muscles, liver, and smooth muscles of bronchus, genitourinary system and uterus and have a higher affinity for epinephrine over norepinephrine
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Beta 2
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What class of drugs are not effective orally because they undergo metabolism by conjugation and oxidation in the GI mucosa and liver?
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Catecholamines
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Why is absorption of catecholamines very slow subQ?
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Causes local vasoconstriction
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What two enzymes metabolize epinephrine?
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COMT (catechol O-methyl transferase)
MAO (mono amine oxidase) excreted in the urine |
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Epinephrine injection is available in what concentrations?
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1:1,000
1:10,000 |
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What are some therapeutic uses of catecholamines?
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Relieve respiratory distress due to bronchospasm
Hypotension Cardiac effects Rapid relief of hypersensitivity rxn to drugs Prolongs the action of local anesthetic drugs Topical hemostatic agent on bleeding surfaces |
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What are some adverse effects of catecholamines?
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fear, anxiety
Hypertension with headache Cerebral haemorrhage Cardiac arrhythmia Necrosis of tissue |
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When are catecholamines contraindicated?
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In pregnancies (incuces contraction of uterus)
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What neurotransmitter is responsible for regulation of movement (motor activity) and is a substrate for both MAO and COMT?
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Dopamine
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At low concentrations what receptor does dopamine interact with?
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D1-dopaminergic receptors
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What effect does dopamine have on the body at low concentrations?
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Increases GFR
Increases renal blood flow Increases Na excretion |
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At medium-high doses what receptor does dopamine interact with?
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B1 receptors, exerts positive inotropic effect on myocardium
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At very high concentrations what receptor does dopamine interact with?
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Alpha1 adrenergic receptors, vasoconstriction
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How is dopamine hydrochloride administered?
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IV ONLY
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What are some therapeutic uses of dopamine?
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Treatment of shock
Beneficial to patients with oliguria |
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When is dopamine contraindicated?
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Avoided in patients receiving MAO inhibitors or taking tricyclic antidepressants
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