CVS 5 Flashcards
(14 cards)
What is the cardiac cycle?
The sequence of pressure and volume changes that take place during cardiac activity
What is systole?
Contraction and emptying
What is diastole?
relaxation and filling
What percent of the cardiac cycle is diastole?
Roughly 60%
When does a valve open?
When pressure is great behind the valve
What is an ECG
A record of the overall spread of electrical activity throughout the heart at any time
What is the P wave on an ECG?
Atrial depolarisation
What is the QRS complex on an ECG?
Ventricular depolarisation
What is the T wave on an ECG?
Ventricular repolarisation
What is the TP Interval on an ECG?
The time during which ventricles are relaxing and filling
What are the five main phases of the cardiac cycle?
1. Filling period (passive filling during ventricular and atrial diastole) 2 .Atrial contraction 3. Isovolumetric ventricular contraction 4. Ejection 5. Isovolumetric ventricular relaxation
(stages 1 & 2 are ventricular filling)
(stage 4 is ventricular emptying)
What is used to detect heart sounds?
A Phonocardiogram
What is the first heart sound?
Closure of the AV valves
-Coincides with the beginning of systole
What is the second heart sound?
Closure of aortic and pulmonary valves
-Coincides with the onset of diastole
