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Old 06-22-2012
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Default Cardiac Cycle

I am watching the Kaplan Physiology video for cardiac cycle and Dr. Kudrath mentions that the closure of mitral valve creates the S1 sound. When I look at the graph the line matches with the opening of the aortic valve creating the S1 sound.

I am confused as to which valve opening/closing is associated with heart sound S1. Please help!
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S1 sound if produced from the closure of the mitral and the tricuspid valves.

S2 is produced from closure of the aortic and pulmonic valves.

S3 is produced from rapid feeling of blood that hit walls of the ventricle during relaxation.

S4 is produced from the atrial contraction.
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Heart sounds occur not due to the closure of the valves but infact due to the turbulent flow CAUSED by the closure of the valve. But since they are so close in approximation & happen literally at the same time, we just say that the closure of the valve causes the heart sound.

S1 occurs after mitral & tricuspid valves close. (end of diastole/beginning of systole)
S2 occurs after aortic & pulmonic valves close. (end of systole/beginning of diastole)
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Quote:
Originally Posted by modesty View Post
S3 is produced from rapid feeling of blood that hit walls of the ventricle during relaxation.

S4 is produced from the atrial contraction.

I thought that S3 is produced by rapid filling and S4 is caused by a stiffened left ventricle so when the blood rushes in it hits the stiff wall & that causes the sound ?
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Quote:
Originally Posted by modesty View Post
S1 sound if produced from the closure of the mitral and the tricuspid valves.

S2 is produced from closure of the aortic and pulmonic valves.

S3 is produced from rapid feeling of blood that hit walls of the ventricle during relaxation.

S4 is produced from the atrial contraction.
Thank you!
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Quote:
Originally Posted by Hope2Pass View Post
Heart sounds occur not due to the closure of the valves but infact due to the turbulent flow CAUSED by the closure of the valve. But since they are so close in approximation & happen literally at the same time, we just say that the closure of the valve causes the heart sound.

S1 occurs after mitral & tricuspid valves close. (end of diastole/beginning of systole)
S2 occurs after aortic & pulmonic valves close. (end of systole/beginning of diastole)
Thank you!
Makes more sense now
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Quote:
Originally Posted by Hope2Pass View Post
I thought that S3 is produced by rapid filling and S4 is caused by a stiffened left ventricle so when the blood rushes in it hits the stiff wall & that causes the sound ?
Yes, cause atrial contraction occurs in response to a stiffened left ventricle. Hope that helps!
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Quote:
I thought that S3 is produced by rapid filling and S4 is caused by a stiffened left ventricle so when the blood rushes in it hits the stiff wall & that causes the sound ?
Towards the end of diastole the atria normally contract, and this 'pumps' out the last bit of blood in the atria into the ventricle. When this blood is pumped into a stiff/hypertrophic ventricle it produces a gallop, which is the s4. The atria are always contracting at the end of diastole in a normal heart, but this doesn't produce a gallop unless there's stiffening of the ventricle.
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