Cardiac Cycle Quiz: Test Your Knowledge of Phases

Study Notes

Stroke volume is the volume of blood ejected from the left ventricle during each contraction (systole).
Cardiac output is the product of heart rate and stroke volume; increasing either heart rate or stroke volume increases cardiac output.
Key events in the cardiac cycle include atrial and ventricular contraction, opening and closing of heart valves, ejection of blood from the ventricles, and relaxation of the heart chambers.

The first heart sound (S1) is produced by the closure of the AV valves (mitral and tricuspid) and is heard at the beginning of systole.
The second heart sound (S2) is produced by the closure of the semilunar valves (aortic and pulmonary) and is heard at the beginning of diastole.
Heart sounds can be heard best at specific locations on the thorax, such as the apex and base of the heart, using a stethoscope.
Blood pressure is influenced by cardiac output, peripheral resistance, blood volume, viscosity of blood, elasticity of arteries, and neural and hormonal regulation.

The normal resting heart rate for adults is typically between 60 and 100 beats per minute.
Blood pressure readings indicate the force of blood against the walls of the arteries; a normal reading for adults is typically below 120/80 mmHg.

Isovolumetric contractions occur when the ventricles contract but do not change in volume.
Isovolumetric relaxation occurs when the ventricles relax but do not change in volume.
Murmurs are abnormal heart sounds caused by turbulent blood flow within the heart.
The dicrotic notch represents the brief rise in aortic pressure that occurs when the aortic valve closes following ventricular ejection.

Pulses are most easily palpated at arterial sites where the artery is close to the body surface, such as the radial artery at the wrist or the carotid artery in the neck.

The cardiac cycle refers to the sequence of events that occur during one complete heartbeat, including diastole and systole of both atria and ventricles.
The phases of the cardiac cycle include atrial systole, ventricular systole, and relaxation periods for both the atria and ventricles.
During atrial systole, the atria contract, pushing blood into the ventricles. Ventricular systole follows, during which the ventricles contract, forcing blood into the arteries. The relaxation periods allow for the chambers to refill with blood.

Cardiac output is the volume of blood pumped by the heart in one minute, calculated by multiplying stroke volume by heart rate.
Blood pressure (BP) is directly influenced by cardiac output (CO) and peripheral resistance (PR); an increase in either CO or PR will lead to an increase in blood pressure, while a decrease in either will lead to a decrease in blood pressure.