10 Questions
What is the primary function of the AV valves closing during ventricular contraction?
To prevent blood from flowing back into the atria
During which part of the cardiac cycle do the semilunar valves close?
During ventricular relaxation and diastole
What is the name of the sound produced by the closing of the AV valves?
S1
What is the purpose of the semilunar valves closing?
To prevent blood from flowing back into the ventricles from the pulmonary artery and aorta
What is the cardiac cycle stage when the lub sound is produced?
Systole
The 'lub' sound is produced during the closure of semilunar valves at the beginning of diastole.
False
During ventricular relaxation, the semilunar valves close to prevent blood from flowing back into the ventricles.
False
The second heart sound (S2) is produced by the closing of the AV valves at the end of systole.
False
The 'dub' sound is generated by the opening of the AV valves during ventricular relaxation.
False
During ventricular contraction, the AV valves snap shut to prevent blood flow from the aorta back into the ventricles.
True
Study Notes
Heart Sounds
- The lub-dub sounds heard during auscultation of the heart are caused by the valves snapping shut.
- "Lub" (S1) is the sound of the AV valves closing during ventricular contraction, at the beginning of systole.
- This prevents blood from flowing back into the atria from the ventricles.
Valve Closures
- AV valves close during ventricular contraction, at the beginning of systole.
- Semilunar valves close during relaxation of ventricles, at the end of systole and beginning of diastole.
- This prevents blood from flowing back into the ventricles from the pulmonary artery and aorta.
Cardiac Cycle
- Ventricular contraction occurs at the beginning of systole.
- Relaxation of ventricles occurs at the end of systole and beginning of diastole.
Test your knowledge on heart sounds and the cardiac cycle. Learn about the 'lub' (S1) and 'dub' (S2) sounds, when AV valves and semilunar valves close, and their significance in the cardiac cycle.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
