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62 Cards in this Set
- Front
- Back
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The ____ wave represents the depolarization of the atria.
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P wave
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Where does depolarization begin in the heart?
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SA node
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Is atrial repolarization seen in a normal ecg?
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No...it is buried in the QRS complex
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The ________ interval is the time from the initial depolarization of the atria to the initial depolarization of the ventricles.
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PR interval
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The PR segment corresponds to an isoelectric (flat) portion signaling _____ _____ conduction.
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AV node
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outline the conduction pathway of a normal action potential through the heart...
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SA node (automatic)
Left atrium depol. Right atrium depol. AV node (very delayed--allows ventricles to fill completely) Bundle of His Left and Right bundle branches left and right purkinje fibers **note that the conductile anatomy is slightly more complicated than the above outline...not likely testable |
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What is the sympathetic effect on the conduction velocity through the AV node? Parasympathetic?
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Symp = faster
Para = slower |
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The QRS waves collectively represent ______________.
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depolarization of the ventricles
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The ____ wave represents repolarization of the ventricles.
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T wave
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The _____ interval represents first ventricular depolarization to last ventricular repolarization.
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QT interval
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The ____ segment corresponds to the plateau of the ventricular action potential.
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ST segment
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________ is the volume of blood ejected by the ventricle on each beat.
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stroke volume
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___________ is the fraction of the end-diastolic volume efected in each stroke volume...a measure of ventricular efficiency.
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Ejection Fraction
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_______ is the total volume ejected by the ventricle per unit time.
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Cardiac Output
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What is an ~ normal EF?
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55%
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Ejection Fraction = _____/______
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Stroke volume/ end-diastol. vol.
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What is an ~ normal cardiac output?
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5L/min
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Cardiac output = _______ x ________.
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Stroke Volume x HR
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Cardiac output is determined by ________ and _______
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CO determined by HR and stroke volume
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________Is the highest pressure during the cardiac cycle and is determined by stroke volume and compliance
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Systolic pressure
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___________ Is the lowest pressure during the cardiac cycle and is determined by heart rate and total peripheral resistance
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Diastolic pressure
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What contributes to arterial pressure?
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Cardiac output
Total peripheral resistance |
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What contributes to stroke volume?
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LVEDV
LVESV |
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What contributes to LVEDV?
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Ventricular compliance
Ventricular filling pressure |
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What contributes to LVESV?
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Vent. Ejection
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Ventricular ejection is dependent on ___________________________?
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Coronary blood flow
Sympathetic discharge |
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What are the 2 steps that influence heart rate?
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Pacemaker freq.
Symp vs. para influence |
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What determines total peripheral resistance?
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Local factors
neurohumoral |
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Blood pressure = __________ x ________________
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Cardiac output
TPR |
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dPressure = ______ x ______
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dP = flow x resistance
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Consider vascular blood flow, where is there no net flow (location/zone)?
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against the wall
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Reynolds # helps to determine what kind of flow...>2000
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Turbulant flow
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Compliance is determined by?
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d Volume
d pressure |
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Arteries or veins have the most compliance?
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Veins
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What contributes to transmural pressure?
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Pi and Po
inside and outside pressures |
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Which vascular structure(s) represent the greatest total surface area?
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Capillaries
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Which vascular structure(s) have the slowest blood flow velocity?
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Capillaries
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Which vascular structure/systems contains the greatest proportion of total blood volume?
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Venous
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In which vascular structure(s) do you see the greatest drop in pressure? Why?
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Arterioles
greatest resistance here... |
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Why would arterial pressure be higher with arteriosclerosis? Lower with Aortic stenosis?
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Arteriosclerosis is narrowing of radius of vessel and decrease in compliance...thus higher pressure.
Aortic stenosis would have lower pressure because decreased stroke volume and normal compliance. |
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What is the difference in resistance for series and parallel?
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Series:
Flow through any segment in series is the same. i.e. = to total flow Parallel: Pressure drop across system is equal, but flows vary for each bed. Pi = Po |
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What factors contribute to tension on a vessel wall?
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total pressure
Radius of vessel |
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What is the most common type of capillary in the body?
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Continuous caps
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Capillary _____ improves diffusion.
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recruitment
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What are the local mechanisms of vasodilation?
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hyperpolarization
increase cAMP or cGMP |
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What are the local facotrs that cause vasodilation?
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Hypoxia
Adenosine CO2 local acidosis EC K+ Autocoids |
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The heart has mostly what kind of adrenergic receptor?
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Beta 1
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What is the only way to increase oxygen to the heart?
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Increase coronary blood flow
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As oxygen consumption increases, _______ increases.
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Coronary blood flow
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Where are the arterial baroreceptors?
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Carotid sinus
Aortic arch |
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Discuss the cascade produced by stretching baroreceptors in the carotid sinus....
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cues cardiac decelerator
parasympathetic surge inhibitory to SA node |
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Discuss the cascade produced by a decrease in arterial pressure...baroreceptors...
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decreased stretch on baro
decrease parasymp. to heart increased HR increase contractility increase TPR venous constriction: decrease venous volume--increase venous return Arterial pressure normalizes |
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_____ = prolonged P-R interval
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first degree heart block
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_______ = dropped beat---
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Second degree heart block
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What would you expect to see on the ECG of a pt with third degree HB?
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A fair distribution of P waves, BUT NO QRST....Missing beats
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SA node falters, and a subsidiary pacemaker takes over
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Escape beat
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Ectopic focus within the ventricular muscle, the QRS complex is wide, bizarre, and unrelated to a preceding P wave
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Ectopic Beat
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Which are the inferior leads?
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II
III aVF |
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Which are the lateral/left leads?
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I
aVL V5 V6 |
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Which are the Right sides leads?
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aVR
V1 |
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How many Precordial/chest leads are there?
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6
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Which are the anterior leads?
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V2
V3 V4 |
