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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 .
Left ventricular end diastolic posterior wall dimension: LVPWd: The thickness of the posterior left ventricular wall. 8.3 mm, [20] Range 7 – 11 mm [21] Mean left ventricular myocardial thickness: Mean LVMT: Average thickness of the left ventricle, with numbers given as 95% prediction interval for the short axis images at the mid-cavity level [22]
The conduction system consists of specialized heart muscle cells, situated within the myocardium. [3] There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular heart rhythms including rhythms that are too fast or too slow.
Trabeculae ratios of capillary-to myocyte differ between the walls of the right and left ventricle. In the left ventricle, each capillary delivers oxygen to one myocyte. However, in the right ventricle the capillary-to myocyte ratio is 0.8 because the right ventricle tissues have a lower oxygen consumption due to a weaker afterload. [6]
The endocardium underlies the much more voluminous myocardium, the muscular tissue responsible for the contraction of the heart. The outer layer of the heart is termed epicardium and the heart is surrounded by a small amount of fluid enclosed by a fibrous sac called the pericardium. [2]
In most fish, the circulatory system is very simple: a two-chambered heart including one atrium and one ventricle. Among sharks, the heart consists of four parts arranged serially: blood flows into the most posterior part, the sinus venosus, and then to the atrium which moves it to the third part, the ventricle, before it reaches the conus ...
The right fibrous trigone is continuous with the central fibrous body. This is the strongest part of the fibrous cardiac skeleton. The upper chambers and lower are electrically divided by the properties of collagen proteins within the rings. The valve rings, central body, and skeleton of the heart consisting of collagen are impermeable to ...
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.