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PART - 2 - Unit V : CH - 15 Body Fluids and Circulation — BIOLOGY STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 ScienceBIOLOGYPART - 2 - Unit V : CH - 15 Body Fluids and Circulation3 Marks
Question
Explain heart sounds.
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Answer

During one cardiac cycle, two types of sounds are produced, which are known as heart sounds.
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(1) First Heart Sound: It marks the beginning of ventricular contraction and is produced when the mitral and tricuspid valves close. This sound is known as "LUBB".
(2) Second Heart Sound: It marks the beginning of ventricular relaxation. This sound is produced by the closure of semilunar valves (SLV) and is heard as "DUBB."

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