Sydänliha

Sydänliha, also known as cardiac muscle or myocardium, is a specialized type of muscle tissue found only in the heart. It is responsible for the rhythmic contractions that pump blood throughout the body. Unlike skeletal muscle, which is under voluntary control, or smooth muscle, which controls involuntary actions in organs like the digestive system, cardiac muscle is involuntary and self-exciting. This means its contractions are not consciously controlled and it can generate its own electrical impulses to initiate a heartbeat.

Structurally, cardiac muscle cells, called cardiomyocytes, are branched and interconnected by specialized junctions called intercalated discs. These discs contain gap junctions that allow electrical signals to pass rapidly from one cell to another, ensuring that the heart muscle contracts in a coordinated and efficient manner. The sarcoplasmic reticulum in cardiomyocytes is less developed than in skeletal muscle, but calcium ions are still crucial for initiating contraction.

The primary function of sydänliha is to generate the force needed for the heart to effectively pump blood. This continuous, tireless work is essential for delivering oxygen and nutrients to all tissues and organs and removing waste products. The unique properties of cardiac muscle, including its automaticity, excitability, conductivity, and contractility, are vital for maintaining life. Conditions affecting sydänliha, such as heart attacks or cardiomyopathies, can have severe consequences for the overall health of an individual.