Lecture 11: Events of The Cardiac Cycle (Hayward) Flashcards Preview

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Flashcards in Lecture 11: Events of The Cardiac Cycle (Hayward) Deck (27)
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1
Q

For ECGs-Lead III involves putting your +/- electrodes on:

A

LA-, LL+

2
Q

An increase in extracellular Na+ –> intracellular Ca conc.?

A

reduce

3
Q

cardiac cycle

A

the repeating cycle of contraction (systole) and relaxation (diastole) which pumps blood through the circulatory system unidirectionally

4
Q

Which valves are open/closed during diastole?

A

AV valves open, semilunar valves closed

5
Q

systole is initiated by:

A

SA node discharge

6
Q

duration of volume injection phase of systole is driven by duration of

A

AP (volume injection will occur when AP is in plateaue phase and will decrease once repolarization occurs)

7
Q

when do ventricles fill?

A

during diastole

8
Q

2 phases of systole

A

isovolumic, volume injection

9
Q

isovolumic phase of systole

A

ventricles begin to contract, pressure in ventricles is greater than P in atria, but lower than P out in vessels

10
Q

volume injection phase of systole

A

valves open because pressure in ventricles becomes greater than P in outside vessels

11
Q

AV valves open during:

A

diastole and atrial contraction

12
Q

5 main phases of cardiac cycle

A

1) ventricular filling (diastole)
2) atrial contraction (diastole)
3) isovolumic ventricular contraction (systole)
4) ventricular ejection (systole)
5) isovolumic ventricular relaxation (diastole)

13
Q

phase 1: ventricular filling (diastole) + ECG

A

AV valves open, ventricles filling. Semilunar valves closed. Flat line/beginning of P in ECG

14
Q

phase 2: atrial contraction (diastole) + ECG

A

SA node fires, atria contract, P in atria higher than it was previously. Ventricles still filling. Semilunar valves still closed. End of P, Q+R waves on ECG

15
Q

phase 3: isovolumic ventricular contraction (systole) + ECG

A

AV valves close as P in Ventricles> P in Atria. Semilunar valves still closed. S wave

16
Q

phase 4: ventricular ejection (systole) + ECG

A

Semilunar valves open, volume ejection from ventricles to vessels. ST, beginning of T on ECG

17
Q

phase 5: isovolumic ventricular relaxation (diastole) + ECG

A

Semilunar valves close as P in ventricles drops and ventricles relax.

18
Q

Interval between systolic periods of the cardiac cycle ____ with increased parasym. drive

A

increases.

19
Q

cardiac cycle length =

A

HR or RR interval

20
Q

a wave***

A

atrial pressure assoc. with atrial contraction

21
Q

c wave ***

A

caused by change in atrial pressure as AV valves close and valve moves slightly back into atrium (pressure wave in atria during ventricular contraction during isovolumic phase)

22
Q

end diastolic volume

A

volume in ventricle at end of diastole

23
Q

what causes first heart sound?

A

mitral valve closing

24
Q

dichrotic nothch

A

pressure wave assoc. with Aortic valve closing

25
Q

Ejection fraction

A

A measure of contractility. Ratio of blood ejected per beat (stroke volume) to volume of blood in the ventricles at the end of diastole (end-diastolic volume). EF = (EDV-ESV)/EDV

26
Q

What causes 2nd heart sound?

A

aortic valve closing

27
Q

end-systolic volume

A

volume in ventricle at end of systole

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