Cardiac Cycle Flashcards

Flashcards covering key vocabulary and concepts related to the cardiac cycle, based on the lecture notes provided.

Electrocardiogram (ECG)

Recording represents a summary of all the electrical activity of the heart

P wave

Atrial depolarization

QRS complex

Ventricular depolarization

T wave

Ventricular repolarization

DIASTOLE

Relaxation of cardiac muscle (ventricles fill with blood)

SYSTOLE

Contraction of cardiac muscle (ventricles propel blood into the great vessels)

CARDIAC CYCLE

All of the events associated with one heartbeat

Wiggers diagram

Graphical representation of the cardiac cycle

Atrial systole

Atria are contracting and ventricles relaxed; Increase in left atrial pressure greater than left ventricular pressure, causes atrial ejection

Ventricular systole

Ventricles are contracting and the atria are relaxing; Causes increase in ventricular pressure causing semilunar valves to open allowing blood flow to the great vessels

ISOVOLUMETRIC CONTRACTION

Left ventricle contraction increases left ventricular pressure, blood pushes up mitral valve - closes

VENTRICULAR EJECTION CONTRACTION

When left ventricular pressure exceeds aortic pressure, aortic valve opens, blood flows out of left ventricle into aorta

Relaxation period - ventricular diastole

Atria and ventricles are relaxing; Ventricles stars repolarizing

ISOVOLUMETRIC RELAXATION

Ventricular pressure falls and the aortic valve close

Ventricular filling (diastole)

Atria is relaxed and receiving blood from veins throughout this time; When left atrial pressure exceeds left ventricular pressure the mitral valve opens

DICROTIC WAVE (NOTCH)

Rebound of blood off the closed cusps of the aortic valve

Cardiac output (CO)

Amount of blood pumped by EACH ventricle per minute

Stroke volume (SV)

Volume of blood pumped by one ventricle with EACH heartbeat