BIOSC-116 Lecture Notes - Lecture 9: Diastole, Auscultation, Lightning
26 Aug 2020
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Document Summary
The heart sounds during the cardiac cycle. S1 = the first heart sound (lub), heard during systole. This sound is due to the closure of the atrioventricular valves (mitral and tricuspid) and the turbulence of the blood hitting those just closed valves. S2 = the second heart sound (dup), heard during diastole. This sound is due to the closure of the semilunar valves (aortic and pulmonic) and the turbulence of the blood hitting those just closed valves. Heart murmurs these are abnormal heart sounds and may be due to valve problems. For example, you may auscultate someone"s chest and hear shh-dup instead of lub-dup . So valve problems can cause murmurs, but not all murmurs are due to a valve problem. For example, a baby born with a patent ductus arteriosus will have a very loud murmur and you will not hear s1 or s2.
