Cardiac Cycle iBook Flashcards

1
Q

Why is the volume of the ventricles never @ 0?

A

there is always some blood in the ventricles

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2
Q

Describe the ECG

A

P wave=atrial depolarization
PR interval=time for AV node transmission
QRS complex=ventricular depolarization
ST segment=when ventricular mycytes @ plataeu
T wave=ventricular repolarization

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3
Q

What is the isoelectric line?

A

time btwn beats, when all chambers of heart are in diastole

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4
Q

When is peripheral run-off @ its lowest?

When is peripheral run-off @ its slowest?

A

@ start of ECG when low aortic pressure

total peripheral resistance is high & blood moves to periphery slowly

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5
Q

What is diastolic BP?

A

aortic pressure measured as blood ejected into aorta from L ventricle

aortic & ventricular pressures are almost equal

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6
Q

What is systolic BP?

A

peak of aortic pressure (after opening of aortic valve)

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7
Q

What is the dicrotic notch?

A

blip in aortic pressure wave produced by closing of aortic valve as ventricle relaxes

pressure in aorta then drops as blood goes into periphery

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8
Q

When does the aortic valve open?

A

when pressure in ventricle exceeds that of the aorta

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9
Q

When does ventricular pressure decrease

A

after the peak systolic pressure occurs

occurs quickly once aortic valve closes

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10
Q

Which pressure remains low throughout the cardiac cycle?

A

atrial pressure

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11
Q

When does the atrial pressure increase?

A

shortly after P-wave occurs due to atrial contraction

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12
Q

What is the c-wave?

A

small sharp increase in atrial pressure that coincides w/ start of ventricular contraction

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13
Q

What occurs during isovolemic/isovolumetric contraction?

A

ventricular pressure is increasingly rapidly & causes AV valve to bulge back into atria

leads to slight increase in atrial pressure

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14
Q

What is the v-wave?

A

increase in atrial pressure b/c AV valve is closed & venous blood is accumulating in atria

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15
Q

How does blood flow into ventricle from atria?

A

b/c during diastole & atrial systole, atrial pressure is greater than that inside the ventricle

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16
Q

What is the end systolic volume (ESV)

A

lowest volume of the ventricle (50mL of blood)

measured after aortic valve closes

17
Q

What is the end diastolic volume? (EDV)

A

volume of blood in ventricle when ventricle is full

18
Q

What is unique about the ventricular systole (isovolumetric contraction)?

A

ventricle is contracting isometrically to increase pressure b/c neither the AV nor the aortic/pulmonary valves are open

19
Q

What is isvolemic relaxation?

A

when ventricular volume doesn’t change as ventricular pressure drops

aortic & pulmonary valves close before AV valves can open

20
Q

When do the AV valves open?

A

when ventricular pressure drops below that in the atria

21
Q

When does the first heart sound occur?

A

assoc w/ closing of AV valves (start of isovolemic contraction)

22
Q

When does the second heart sound occur?

A

assoc w/ closing of aortic/pulmonic valves

when dicrotic notch occurs in aortic pressure wave

23
Q

When does the third heart sound occur?

A

period of rapid filling & occurs early in diastole

24
Q

When does the fourth heart sound occur?

A

assoc w/ blood being forced into ventricle during atrial contraction