Term
| what are the four stages of the cardiac excitation sequence? |
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Definition
1. atrial excitation (SA node)
2. AV nodal delay
3. initial ventricular excitation (bundle branches)
4. complete ventricular excitation |
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Term
| how is contraction different between left and right ventricles? |
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Definition
| the LV contracts using its entire perimeter, whereas the RV only uses the one free wall |
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Term
| true or false, left and right ventricular wall thickness does not vary between newborns and adults? |
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Definition
| false, it does not vary in newborns, but it does vary between adults |
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Term
| what are the isometric periods of the cardiac cycle and when do they occur? |
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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 |
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Term
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Definition
| period where ventricular and aortic pressure intersect, it marks the start of isovolumic relaxation in which the aortic valve closes |
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Term
| what is the dicrotic notch? |
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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 |
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Term
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Definition
| the period of slow passive filling of the ventricles |
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Term
| how does exercise affect diastasis and what is the significance? |
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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 |
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Term
| what are two ways stroke volume can be increased? |
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Definition
by increasing the preload (end diastolic volume)
and by increasing the contractility |
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Term
| what are systolic/diastolic reserve capacity? |
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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 |
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Term
| define ejection fraction. |
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Definition
| stroke volume / end diastolic volume |
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Term
| what affect does ventricular contraction have on atrial pressure and why? |
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Definition
| contraction causes a slight elevation in atrial pressure due to the bulging of the AV valves |
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Term
| what are the different parts of the atrial pressure curve? |
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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 |
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Term
| which valve functions occur during isovolumic contraction? |
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Definition
| begins with mitral valve closure and ends with aortic valve opening |
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Term
| which valve functions occur during isovolumic relaxation? |
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Definition
| begins with aortic valve closure and ends with mitral valve opening |
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Term
| how do the functions of the right side heart valves compare with the left side? |
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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 |
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Term
| what happens to the pulse pressure and mean arterial pressure as the blood moves through the arterial system and what causes this effect? |
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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 |
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Term
| what is the reflective wave theory? |
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Definition
| it is a heightening of highs and a lowering of lows due to reflected waves (wave interference) |
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Term
predict the effects of changes in the:
aortic distensibility
stroke volume
heart rate
peripheral resistance
ejection velocity |
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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 |
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Term
what affects do the following have on BP?
arteriosclerosis
aortic insufficiency
hypertension
chronic hypertension |
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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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