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Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart .
Simply put, the dense connective tissue within the cardiac skeleton does not conduct electricity and its deposition within the myocardial matrix is not accidental. The anchored and electrically inert collagen framework of the four valves allows normal anatomy to house the atrioventricular node (AV node) in its center.
The endocardium, by secreting endothelins, may also play a role in regulating the contraction of the myocardium. [8] The swirling pattern of myocardium helps the heart pump effectively. The middle layer of the heart wall is the myocardium, which is the cardiac muscle—a layer of involuntary striated muscle tissue surrounded by a framework of ...
The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.
Through transmembrane proteins in the plasma membrane, the actin skeleton inside the cell is connected to the basement membrane and the cell's exterior. At each end of the muscle fibre, the surface layer of the sarcolemma fuses with a tendon fibre, and the tendon fibres, in turn, collect into bundles to form the muscle tendons that adhere to bones.
Trabeculae lie at the interface between intracardiac flow and the compact myocardium. Their fractal branching pattern helps to maintain cardiac performance in both healthy and failing hearts by increasing contractility and stroke work. [ 3 ]
By this model, if myocardial performance changes while preload, afterload, heart rate, and conduction velocity are all held constant, then the change in performance must be due to a change in contractility. However, changes in contractility alone generally do not occur. [citation needed] Other examples: