15 Questions
What defines the four phases of the cardiac cycle?
Opening and closing of the cardiac valves
What causes the P wave in the electrocardiogram?
Spread of depolarization through the atria
What initiates contraction of the ventricles in the cardiac cycle?
Electrical depolarization of the ventricles
Which wave in the electrocardiogram marks the onset of ventricular systole?
QRS waves
During which phase of the cardiac cycle does the heart fill with blood?
Diastole
What is the period of rapid ejection during ventricular contraction called?
Period of isovolumic contraction
What causes the v wave in the atria?
Slow flow of blood into the atria from the veins during ventricular contraction
What happens during the period of isovolumic or isometric relaxation?
The ventricular muscle relaxes while the volume remains constant
What is the function of the A-V valves?
Prevent backflow of blood from the ventricles to the atria during systole
What causes the c wave in the atria?
Bulging of the A-V valves backward toward the atria due to increasing pressure in the ventricles
What causes the first heart sound?
Rapid closure of the A-V valves at the beginning of systole
Why is the second heart sound shorter in duration than the first heart sound?
The semilunar valves vibrate for a shorter time than the A-V valves
What is the mechanism behind the third heart sound?
Oscillation of blood initiated by inrushing blood from the atria
How does mitral regurgitation affect heart sounds?
It causes a high-frequency blowing sound transmitted most strongly into the left atrium
What condition creates a nozzle effect during systole, leading to intense vibration and a loud murmur?
Aortic stenosis
Test your knowledge about the cardiac events and heart sounds that occur during the cardiac cycle. Learn about the phases of the cardiac cycle and the role of cardiac valves.
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