This blood supply is provided by the coronary arteries. The inner layer of the heart wall is the endocardium, composed of endothelial cells that provide a smooth, elastic, non-adherent surface for blood collection and pumping.
The endocardium may regulate metabolic waste removal from heart tissues and act as a barrier between the blood and the heart muscle, thus controlling the composition of the extracellular fluid in which the cardiomyocytes bathe. This in turn can affect the contractility of the heart. This tissue also covers the valves of the heart and is histologically continuous with the vascular endothelium of the major blood vessels entering and leaving the heart.
The Purkinje fibers are located just beneath the endocardium and send nervous impulses from the SA and AV nodes outside of the heart into the myocardial tissues. The endocardium can become infected, a serious inflammatory condition called infective endocarditis. This and other potential problems with the endocardium may damage the valves and impair the normal flow of blood through the heart. Learning Objectives Distinguish between the epicardium, myocardium, and endocardium layers of the heart wall.
Key Points The epicardium is a thin layer of connective tissue and fat serving as an additional layer of protection for the heart. It is considered a continuation of the serous pericardium. The myocardium is the muscle tissue of the heart, composed of cardiac muscle cells called cardiomyocytes that receive nervous stimulation from the sinoatrial SA and atrioventricular AV nodes via the Purkinje fibers. Cardiomyocytes are shorter than skeletal myocytes, and contain fewer nuclei. Cardiac muscle is striated.
The endocardium is composed of endothelial cells that provide a smooth, non-adherent surface for blood collection and pumping and may help regulate contractility. An infection or inflammation of the endocardium is called infective endocarditis. Epicardium The Heart Wall : The wall of the heart is composed of three layers, the thin outer epicardium, the thick middle myocardium, and the very thin inner endocardium.
It is composed of cardiac muscle fibers, which enable heart contractions. The myocardium is the thickest layer of the heart wall, with its thickness varying in different parts of the heart. The myocardium of the left ventricle is the thickest, as this ventricle is responsible for generating the power needed to pump oxygenated blood from the heart to the rest of the body. Cardiac muscle contractions are under the control of the peripheral nervous system , which directs involuntary functions including heart rate.
Cardiac conduction is made possible by specialized myocardial muscle fibers. These fiber bundles, consisting of the atrioventricular bundle and Purkinje fibers, carry electrical impulses down the center of the heart to the ventricles.
These impulses trigger the muscle fibers in the ventricles to contract. Endocardium endo-cardium is the thin inner layer of the heart wall. This layer lines the inner heart chambers, covers heart valves , and is continuous with the endothelium of large blood vessels. The endocardium of heart atria consists of smooth muscle, as well as elastic fibers. An infection of the endocardium can lead to a condition known as endocarditis. Endocarditis is typically the result of an infection of the heart valves or endocardium by certain bacteria , fungi , or other microbes.
Endocarditis is a serious condition that can be fatal. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads.
Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Regina Bailey. Biology Expert. Regina Bailey is a board-certified registered nurse, science writer and educator. The Layers of the Heart Wall The heart wall is composed of connective tissue , endothelium , and cardiac muscle. Epicardium: the outer protective layer of the heart.
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