Südamekontraktiilsus
Südamekontraktiilsus refers to the intrinsic ability of the heart muscle cells, or cardiomyocytes, to shorten and generate force. This property is crucial for the heart's function as a pump, enabling it to effectively eject blood into the circulatory system with each beat. Unlike skeletal muscle, which relies on external signals for contraction, cardiac muscle possesses inherent contractility. This is regulated by a complex interplay of intracellular calcium levels, the force-generating capacity of the contractile proteins actin and myosin, and the electrical activity of the heart. The strength of contraction can be modulated by various factors, including the Frank-Starling mechanism, where increased ventricular filling leads to a stronger contraction. Neurotransmitters like norepinephrine and hormones such as thyroid hormones can also augment or decrease myocardial contractility. Conditions that impair Südamekontraktiilsus, such as heart failure or myocardial infarction, can lead to reduced cardiac output and various symptoms of cardiovascular disease. Understanding Südamekontraktiilsus is fundamental to comprehending cardiac physiology and pathology.