Myocardium
Encyclopedia : M : MY : MYO : Myocardium
Myocardium is the muscular tissue of the heart. Other tissues are the endocardium (inner lining, effectively a specialised endothelium) and the pericardium (a connective tissue layer around the heart).
The myocardium is composed of specialized cardiac muscle cells with an ability not possessed by muscle tissue elsewhere in the body. Cardiac muscle, like other muscles, can contract, but it can also conduct electricity, like nerves.
The blood supply of the myocardium is by the coronary arteries. If these arteries are occluded by atherosclerosis and/or thrombosis, this can lead to angina pectoris or myocardial infarction.
Certain virusus lead to inflammation of the myocardium, or myocarditis.
Failure of the heart to contract properly (for various reasons) is termed heart failure, generally leading to fluid retention, edema, pulmonary oedema, renal insufficiency, hepatomegaly, a shortened life expectancy and decreased quality of life.
| Cardiovascular system - Heart - [http://encycl.opentopia.com/ edit] |
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| atria (interatrial septum) | ventricles (interventricular septum) | valves (chordae tendinae, papillary muscle)
right heart: (vena cavae, coronary sinus) → right atrium (fossa ovalis) → tricuspid valve → right ventricle → pulmonic valve
left heart: (pulmonary veins) → left atrium → mitral valve → left ventricle → aortic valve pericardium | epicardium | endocardium | myocardium conduction system: cardiac pacemaker | Purkinje fibers | bundle of His | SA node | AV node |
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