hjertemuscle

Hjertemuscle, also known as cardiac muscle or myocardium, is a specialized type of muscle tissue found exclusively in the heart of mammals and other vertebrates. It is responsible for the heart's ability to pump blood throughout the body. Unlike skeletal muscle, which is under voluntary control, or smooth muscle, which regulates internal organ functions, cardiac muscle is involuntary, meaning its contractions are not consciously controlled.

The cells that make up hjertemuscle, called cardiomyocytes, are striated, similar to skeletal muscle, but they have unique characteristics. Cardiomyocytes are branched and interconnected by specialized junctions called intercalated discs. These discs contain gap junctions, which allow electrical signals to pass rapidly from one cell to another, enabling the heart to contract in a coordinated and rhythmic manner. This coordinated contraction is essential for efficient blood circulation.

Hjertemuscle possesses remarkable endurance and resistance to fatigue. It contracts approximately 100,000 times per day without rest, delivering oxygen and nutrients to every cell in the body. The energy required for these continuous contractions is supplied by a high density of mitochondria within the cardiomyocytes, which efficiently process oxygen and fuel. Damage to hjertemuscle, such as that occurring during a heart attack, can impair the heart's pumping function and have serious health consequences.