Lecture 2 - Cardiovascular extra flashcards

What happens during late diastole?

Both sets of heart chambers are relaxed and the ventricles fill passively with blood.

What happens during atrial systole?

Atrial contraction forces a small additional amount of blood into the ventricles.

What happens during isovolumic ventricular contraction?

Ventricular contraction begins—pressure rises, pushing the AV valves closed, but it is not yet high enough to open the semilunar valves.

What occurs during ventricular ejection?

Ventricular pressure rises and exceeds arterial pressure, forcing the semilunar valves open so blood is ejected into the arteries.

What happens during isovolumic ventricular relaxation?

Ventricles relax, ventricular pressure falls, and blood flows back into the cusps of the semilunar valves, snapping them closed.

What does S₁ (the first heart sound) represent?

Closure of the AV valves at the start of ventricular systole (“lub”).

What does S₂ (the second heart sound) represent?

Closure of the semilunar valves at the start of ventricular diastole (“dub”).

What is the sequence of one complete cardiac cycle?

Late diastole → Atrial systole → Isovolumic ventricular contraction → Ventricular ejection → Isovolumic ventricular relaxation → back to diastole.