ydín

Ydän is the Finnish term for the heart, the muscular organ that forms the core of the circulatory system. It pumps blood to the lungs and to the rest of the body, enabling oxygen delivery and nutrient transport.

The heart has four chambers: two atria and two ventricles. Valves ensure one-way blood flow between chambers and into the major arteries: the atrioventricular valves between atria and ventricles, and the semilunar valves at the exits to the pulmonary artery and aorta. The heart sits in the chest cavity, tilted slightly to the left.

The heartbeat is driven by electrical impulses that start in the sinoatrial node, spread to the atrioventricular node, and travel through conduction pathways to coordinate atrial and ventricular contraction. This cycle creates systole and diastole, maintaining circulation.

The heart rate and force are regulated by the autonomic nervous system and hormones. Common conditions affecting ydän include coronary artery disease, arrhythmias, and heart failure. Diagnosis uses electrocardiography, echocardiography, and imaging; treatment ranges from lifestyle changes to medications and surgery.