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Cardiopulmonary 11
Cardiac Cycle
20
Medical
Graduate
12/09/2012

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Cards

Term
what are the four stages of the cardiac excitation sequence?
Definition
1. atrial excitation (SA node)
2. AV nodal delay
3. initial ventricular excitation (bundle branches)
4. complete ventricular excitation
Term
how is contraction different between left and right ventricles?
Definition
the LV contracts using its entire perimeter, whereas the RV only uses the one free wall
Term
true or false, left and right ventricular wall thickness does not vary between newborns and adults?
Definition
false, it does not vary in newborns, but it does vary between adults
Term
what are the isometric periods of the cardiac cycle and when do they occur?
Definition
when all of the heart valves are closed and the volume inside of the ventricles is constant

isovolumic contraction occurs during systole when the LV begins contracting until the aortic valve opens

isovolumic relaxation occurs during diastole when the LV is relaxing until the AV valve opens
Term
define protodiastole.
Definition
period where ventricular and aortic pressure intersect, it marks the start of isovolumic relaxation in which the aortic valve closes
Term
what is the dicrotic notch?
Definition
it is the second peak in the aortic pressure curve due to the back flow of blood into the LV and the closing of the aortic valve, it causes a small spike in pressure
Term
define diastasis.
Definition
the period of slow passive filling of the ventricles
Term
how does exercise affect diastasis and what is the significance?
Definition
the period is shortened due to elevated HR, because this is a slow passive portion, the preload on the heart is not affected as much as if the active filling portion were shortened
Term
what are two ways stroke volume can be increased?
Definition
by increasing the preload (end diastolic volume)
and by increasing the contractility
Term
what are systolic/diastolic reserve capacity?
Definition
systolic - the amount of blood left that can be ejected after systole

diastolic - the amount of extra blood that can fill the LV during diastole
Term
define ejection fraction.
Definition
stroke volume / end diastolic volume
Term
what affect does ventricular contraction have on atrial pressure and why?
Definition
contraction causes a slight elevation in atrial pressure due to the bulging of the AV valves
Term
what are the different parts of the atrial pressure curve?
Definition
c wave - rapid elevation due to ventricular contraction

v wave - slow elevation due to atrial filling

a wave - rapid elevation due to atrial contraction
Term
which valve functions occur during isovolumic contraction?
Definition
begins with mitral valve closure and ends with aortic valve opening
Term
which valve functions occur during isovolumic relaxation?
Definition
begins with aortic valve closure and ends with mitral valve opening
Term
how do the functions of the right side heart valves compare with the left side?
Definition
the tricuspid valve closes shortly after the mitral valve
the pulmonic valve opens shortly before the aortic valve

the pulmonic valve closes shortly after the aortic valve
the tricuspid valve opens shortly before the mitral vavle
Term
what happens to the pulse pressure and mean arterial pressure as the blood moves through the arterial system and what causes this effect?
Definition
there is an increase in the pulse pressure (spreading out of systolic and diastolic) and a reduction in the mean arterial pressure

it is caused by the resistance of blood flow to a region due to blood having to be forced out of the region
Term
what is the reflective wave theory?
Definition
it is a heightening of highs and a lowering of lows due to reflected waves (wave interference)
Term
predict the effects of changes in the:
aortic distensibility
stroke volume
heart rate
peripheral resistance
ejection velocity
Definition
high pulse pressure is caused by all of the following

low distensibility
increased stroke volume
slow heart rate
low peripheral resistance
fast ejection velocity
Term
what affects do the following have on BP?
arteriosclerosis
aortic insufficiency
hypertension
chronic hypertension
Definition
high systolic and pulse pressures
low diastolic, high systolic, high pulse pressure
high diastolic, high systolic, low pulse pressure
high pulse pressure
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