Download MBBS Physiology Presentations 15 Heart Sounds And Murmurs Lecture Notes

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Heart Sounds & Murmurs

Department of Physiology

Heart Sounds


Heart sounds

? S1 ? "lubb" caused by the closing of the AV valves
? S2 ? "dupp" caused by the closing of semilunar valves
? S3 ?associated with blood flowing into the ventricles
? S4 ?associated with atrial contraction

Four heart sounds can be recorded by phonocardiography,

but normally only the first and the second heart sounds,

are audible through a stethoscope

First heart sound

? occurs when the

atrioventricular (AV) valves

close at the beginning of

ventricular contraction

? generated by the vibration of

the blood and the ventricular

wal

? is louder, longer, more in

duration than the second heart

sound


Second heart sound

? occurs when aortic and

pulmonary semilunar valves

close at the beginning of

ventricular dilation

? generated by the vibration of

the blood and the aorta

? Aortic valve closes slightly

before pulmonary valve

? Splitting of S2

Heart Murmur

? Cardiac murmurs are abnormal heart sounds in the form

of noises resulting from turbulent blood flow,

? Murmurs may be:

? Systolic murmurs, if they occur during systole.
? Diastolic murmurs, if they occur during diastole

? Causes:

? Stenosis (narrowing) of heart valves
? Incompetence of heart valves
? Increase of blood flow or decrease of blood viscosity (as in anemia).


Two Basic Types of Valvular Diseases

valvular stenosis:
? narrowing of the valve

valvular insufficiency

(incompetence):
? valve is unable to

close fully; so there is

regurgitation

Phonocardiograms examples
Thank You