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19 Cards in this Set
- Front
- Back
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Arteriography shows narrowing of radius by 50%. What is the expected change in blood flow?
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Decrease radius by 1/2-->Increase resistance 1/16
Thus flow will decrease to 1/16 |
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When a person moves from a supine position to a standing position, what compensatory changes occur?
Why? |
Standing will DECREASE venous return, DECREASE cardiac output, DECREASE arterial pressure
Need to INCREASE contractility to INCREASE HR |
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What does an increased ejection fraction signify?
What is its effect on end-systolic volume? |
EF = SV/EDV
An increase in EF means a higher fraction of end-diastolic volume is ejected in stroke volume (could be due to administration of a positive inotropic agent). When this occurs, the volume remaining in the ventricle after systole DECREASES. |
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If HR is 70 bpm, calculate cardiac output.
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SV = 140-60 = 80
Q = 80 * 70 = 5600 mL = 5.6 L |
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The ventricles are completely depolarized in which isoelectric portions of the EKG?
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Only isoelectric segments of EKG are PR and ST
Ventricular depol occurs during ST |
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Patient develops orthostatic hypotension after sympathectomy.
This is due to a/n [exaggerated/suppressed] response of the baroreceptor mechanism. |
Suppressed bc no longer has sympathetic circuit to increase HR/contractility
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The dashed line in the figure illustrates the effect of __________.
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Increased contractility
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The dashed line in the figure illustrates __________.
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Increased blood volume, thus, increased mean systemic pressure
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How can venous pressure be modified to increase tendency for edema to occur?
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Increased venous pressure will increase tendency for edema.
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The upstroke of the action potential in the SA node is due to the influx of ______.
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Ca2+
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The upstroke of the action potential in Purkinje Fibers is due to influx of ______.
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Na+
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In the SA node, phase 4 depolarization is attributable to ______.
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Increase in Na+ conductance
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alpha1 vs beta2 effects
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alpha1: Vasoconstriction of arteriolar smooth muscle
beta2: VasoDILATION of arteriolar smooth muscle |
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During which phase of the cardiac cycle is aortic pressure highest?
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Reduced ventricular ejection (right after rapid ventricular ejection ends)
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What is the effect of histamine on arterioles?
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Dilation
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During which phase of the cardiac cycle is ventricular volume lowest?
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Isovolumetric ventricular relaxation; volume ;lowest when ventricle is relaxed (diastole)
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During which phase of the ventricular action potential is the conductance to Ca2+ highest?
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Phase 2 of plateau (right before repolarization)
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Aldosterone vs ADH
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ADH: increase arterial bp, increases water permeability of distal tubule and collecting ducts
Aldosterone: Indirectly increases water resorption via retention of Na+ |
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EF 0.4
HR 95 bpm Q 3.5 L/min EDV? |
EF = SV/EDV
Q = HR x SV =92 mL |
