Heart sounds
The characteristic "lub-dub " sound of the heart is created by the closing of the valves. The "Lub" sound marks the start of the contraction of the ventricles, known as ventricular systole. The sound is caused by the closure of the valves separating each ventricle from its atrium. The two valves are the mitral and tricuspid valves. The tricuspid valve separates the right atrium from the right ventricle while the mitral valve separates the left atrium from the left ventricle. Scan the image on the right to identify the valves.
The second "Dub" sound marks the start of the relaxation of the ventricles known as ventricular diastole. The sound is caused by the closure of the pulmonary and aortic valves. These valves prevent blood from rushing back into the ventricles after contraction has occurred. Click on the image on the right to hear a healthy heart beat.
The period of relaxation (diastole) is longer than the period of contraction(systole). So a pause is heard after the "Lub -Dub".
The heart beat sounds like "Lub -Dub", pause, "Lub -Dub", pause and so on.
Doctors can tell a great deal about the health of a patient's heart by simply listening to the sound of the heart beat. You can hear different heart beats by a simple click on the links below.
| Normal healthy heart beat | Can you identify the moments where the valves close? |
| A patient with an aortic valve that is not functioning properly. | What can be the outcome if the aortic valve is not functioning properly? |
| A patient with a condition known as aortic stenosis. This condition causes the aorta to become narrow with the space inside the artery severely diminished. During systole (contraction of the ventricles) blood is squeezed through a small opening at very high speed. This causes intense vibrations and a loud murmur occurs. | What are the symptoms if blood can not be pumped into the aorta in sufficient volume? |
| The heart is an organ that is involved in | |
| Which major blood vessel takes blood out of the right ventricle? | |
| The blood vessel that takes blood to the left atrium is called the | |
| The blood flowing into the left atrium is | |
| The pulmonary vein contains | |
| The right ventricle pumps blood into the | |
| The heart has | |
| An atrium has |