what makes the sound of a heart beat
Heart sounds In healthy adults, there are two normal heart sounds, often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4.
Heartbeat (novel) Twelve-year-old Annie is having a very significant year. Her mother is pregnant, her grandfather is forgetful, her best friend is always moody, and she has a new art assignment-draw an apple each day for one hundred days.