szívizomkontrakciójukat

Szívizomkontrakció refers to the process by which the heart muscle contracts, leading to the pumping of blood throughout the body. This vital physiological function is a complex, coordinated event involving electrical and mechanical components.

The cardiac cycle begins with electrical impulses originating in the sinoatrial (SA) node, often called the heart's natural pacemaker. These impulses spread through specialized conducting pathways in the atria, causing them to contract and push blood into the ventricles. The electrical signal then travels to the atrioventricular (AV) node, where it is briefly delayed, allowing the ventricles to fill completely.

Following the delay at the AV node, the impulse is rapidly conducted through the ventricles via the bundle of His and Purkinje fibers. This electrical activation triggers the mechanical contraction of the ventricular muscle. The ventricles then forcefully eject blood into the pulmonary artery (from the right ventricle to the lungs) and the aorta (from the left ventricle to the rest of the body).

The relaxation phase, known as diastole, follows contraction (systole). During diastole, the heart muscle relaxes, and the chambers refill with blood, preparing for the next cycle of contraction. This rhythmic sequence of contraction and relaxation ensures continuous blood circulation, supplying oxygen and nutrients to all tissues and organs. The force and rate of szívizomkontrakció are regulated by the autonomic nervous system and various hormones, allowing the heart to adapt to the body's changing needs.