The blood rushing through the valves as the open and close - thump-thump-thump. . .
Abnormal sounds may be heard before, after, or during the normal heart sounds. For instance, sounds associated with stenosis may be heard before the closing of that valve.
Mostly turbulence, but the sounds of the valves closing can also be heard.
Your heart beat of course.
The valves opening and closing
Apex
Lubb dubb corresponds to the heart sounds heard during systole and diastole, respectively.
Actually , the heart beat is heard when the heart valves closes ! The sounds are described as "lupp-dupp"
Normal heart sounds are caused by the heart beating. This is the process of the heart muscle contracting and relaxing as blood flows through the various chambers.
The normal heart sounds are described as a lubb dubb. These sounds are due to the closing of the valves. If a murmur is heard, the valves are not closing properly and there is a back flow of blood. Also if the normal heart sounds are not in a rhythm, there is something wrong with the way the heart is working.
when a doctor listens to the chest with a stethoscope during the Valsalva maneuver, characteristic heart sounds are heard. Variations in these sounds can indicate the type of abnormality present in the heart.
A heart murmurs is an abnormal sound consisting of a clicking, rushing, or gurgling noise that either is heard before, between , or after the normal sounds, or may may mask the normal heart sounds.
Crepitus.Abnormal crackling sounds are called rales when heard on ausculation of the lungs, but called crepitus when heart in a joint, gangrenous skin, etc.