The Cardiac Cycle

These flashcards cover key terms and concepts related to the cardiac cycle, including definitions of important phases, diagrammatic representations, and physiological principles.

Cardiac Cycle

The sequence of electrical and mechanical events that occur with each heartbeat.

Systole

The phase of ventricular contraction in the cardiac cycle.

Diastole

The phase of ventricular relaxation and filling in the cardiac cycle.

Wiggers Diagram

A diagram used in cardiac physiology that plots time against various cardiac pressures and volumes.

End-Diastolic Volume (EDV)

The maximal blood volume in a ventricle at the end of diastole.

End-Systolic Volume (ESV)

The minimal blood volume remaining in a ventricle at the end of systole.

Stroke Volume (SV)

The volume of blood ejected by the left ventricle with each heartbeat; calculated as EDV - ESV.

Preload

The initial stretching of the cardiac myocytes prior to contraction due to the volume of blood in the ventricle.

Afterload

The load against which the heart must contract to eject blood, primarily determined by arterial resistance.

Inotropy

The force of muscle contraction; changes in inotropy affect stroke volume independently of muscle length.

Phase 1:

IVCT

Phase 2:

IVCT

Phase 3:

rapid ejection

Phase 4:

reduced ejection

Phase 5:

IVRT

Phase 6

Rapid Filling -

Phase 7:

Reduced Filling -

atrial contraction is initiated by

P wave

cardiac output is equal to stroke volume time HR

true

The part of the cardiac cycle where all valves are closed and the S1 sound of the heart is heart is called

IVCT

The aortic valve opens

When the ventricular pressure exceeds the pressure in the aorta

the mitral valve closes when

the pressure in the LV exceeds the pressure in the LA

LV volume is at its minimum during

IVRT

the s1 sound is caused by

opening of the Atrioventicular valves