Blood pressure Flashcards
Blood pressure in any chamber
Rises during systole
* Falls during diastole
Blood flows from high to low pressure and is
Controlled by timing of contractions
* Directed by one-way valves
Cardiac Cycle and Heart Rate is at ____and last___
At 75 beats per minute (bpm)
* Cardiac cycle lasts about 800 msec
When heart rate increases
All phases of cardiac cycle shorten, particularly diastole
Atrial Systole step 1
Atrial contraction begins
* Right and left AV valves are open
atrial systole part 2:Atria eject blood into ventricles
Filling ventricles
Atrial systole step 3: Atrial systole ends
AV valves close
* Ventricles contain maximum blood volume
* Known as end-diastolic volume (EDV
VNTRICULAR SYSTOLE (step 4 of atrial systole)
Ventricles contract and build pressure
* AV valves close cause isovolumetric contraction
Ventricular ejection (atrial systole part 5)
Ventricular pressure exceeds vessel pressure opening the
semilunar valves and allowing blood to leave the ventricle
* Amount of blood ejected is called the stroke volume (SV)
- Ventricular pressure falls
Semilunar valves close
* Ventricles contain end-systolic volume (ESV), about 40%
of end-diastolic volume
- Ventricular diastole
Ventricular pressure is higher than atrial pressure
* All heart valves are closed
* Ventricles relax (isovolumetric relaxation)
- When Atrial pressure is higher than ventricular pressure
AV valves open
* Passive atrial filling
* Passive ventricular filling
S1
Loud sounds
* Produced by AV valves
- S2
Loud sounds
* Produced by semilunar valves
Cardiac Output (CO)
The volume pumped by left ventricle in 1 minute
