Szívizomszálak

Szívizomszálak refer to the specialized muscle fibers that make up the cardiac muscle tissue of the heart. These fibers are distinct from skeletal muscle fibers and smooth muscle fibers, possessing unique structural and functional characteristics suited for the continuous and involuntary pumping action of the heart. Each szívizomszál is a single, multinucleated cell, often referred to as a cardiomyocyte. These cells are interconnected by specialized junctions called intercalated discs, which facilitate rapid electrical signal transmission between cells. This allows the heart to contract as a coordinated unit.

The cytoplasm of szívizomszálak is rich in mitochondria, reflecting the high energy demand of the heart. These organelles are responsible for generating ATP, the energy currency of the cell, through aerobic respiration. The contractile elements within szívizomszálak are myofibrils, which are composed of repeating units called sarcomeres. The arrangement of actin and myosin filaments within sarcomeres is similar to that of skeletal muscle, enabling contraction through the sliding filament mechanism. However, unlike skeletal muscle, cardiac muscle is not under voluntary control; its contraction is regulated by the heart's intrinsic electrical conduction system and influenced by the autonomic nervous system and hormones. The unique structure and properties of szívizomszálak are essential for maintaining circulatory function throughout the body.