Sydämenlyönnit

Sydämenlyönnit refer to the rhythmic contractions and relaxations of the heart that pump blood throughout the body. Each beat is a complex event involving the coordinated electrical and mechanical activity of the heart muscle. The electrical impulse originates in the sinoatrial (SA) node, the heart's natural pacemaker, and travels through the atria, causing them to contract. This electrical signal then reaches the atrioventricular (AV) node, where it is briefly delayed, allowing the ventricles to fill completely. Finally, the impulse spreads through the ventricles, initiating their contraction and pumping blood into the aorta and pulmonary artery.

The rate of sydämenlyönnit is known as the heart rate, typically measured in beats per minute (bpm). A normal resting heart rate for adults usually falls between 60 and 100 bpm, though this can vary based on factors such as age, fitness level, and emotional state. Physical activity, stress, fever, and certain medications can all increase heart rate, while sleep and relaxation can lower it. Deviations from the normal heart rate, such as a rate that is consistently too fast (tachycardia) or too slow (bradycardia), can sometimes indicate underlying health conditions and may warrant medical attention. The sound of sydämenlyönnit, often described as "lub-dub," is produced by the closing of the heart valves as blood flows through the chambers.