Hjärtmuskulaturen

Hjärtmuskulaturen is the specialized muscle tissue that forms the walls of the heart. It is also known as cardiac muscle. Unlike skeletal muscle, which is under voluntary control, or smooth muscle, found in organs like the digestive tract, cardiac muscle is involuntary. This means its contractions are not consciously directed by the individual.

The primary function of hjärtmuskulaturen is to pump blood throughout the body. This is achieved through rhythmic and coordinated contractions and relaxations. The muscle fibers of the heart are arranged in a complex network that allows for efficient electrical conduction, ensuring that each part of the heart contracts in the correct sequence.

Histologically, hjärtmuskulaturen exhibits characteristics of both skeletal and smooth muscle. Its fibers are striated, similar to skeletal muscle, due to the organized arrangement of contractile proteins actin and myosin. However, these fibers are shorter and branched, and they connect to each other via specialized junctions called intercalated discs. These discs contain gap junctions, which allow electrical impulses to pass rapidly from one cell to another, enabling the heart to function as a single, coordinated unit.

The cells of hjärtmuskulaturen are also highly resistant to fatigue, as they are rich in mitochondria, the powerhouses of the cell, which provide the necessary energy for continuous pumping. The heart muscle receives a rich supply of oxygen and nutrients via the coronary arteries. Damage to this muscle, such as from a myocardial infarction (heart attack), can impair its pumping ability and have severe consequences for the body's circulatory system.