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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 .
The inner endocardium lines the cardiac chambers, covers the cardiac valves, and joins with the endothelium that lines the blood vessels that connect to the heart. On the outer aspect of the myocardium is the epicardium which forms part of the pericardial sac that surrounds, protects, and lubricates the heart. [1]
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 ...
These categories are called epicardial (above the epicardium, or the outermost tissue of the heart) and microvascular (close to the endocardium, or the innermost tissue of the heart). [ 2 ] Reduced function of the coronary arteries can lead to decreased flow of oxygen and nutrients to the heart.
After a short delay that gives the ventricles time to fill with blood, the electrical signal diverges and is conducted through the left and right bundle branches of His to the respective Purkinje fibers for each side of the heart, as well as to the endocardium at the apex of the heart, then finally to the ventricular epicardium; causing the ...
Then mesothelial cells form the pericardium and migrate to form most of the epicardium. Then the heart tube is formed by the endocardium, which is the inner endothelial lining of the heart, and the myocardial muscle wall which is the epicardium that covers the outside of the tube. [7]
Whatever the case, the heart needs blood, and if we look at the heart wall, there’s three layers—the outermost layer, the epicardium, then the myocardium in the middle, and the endocardium inside the heart. The coronary arteries start up in the epicardium, and then dive down and supply all the heart tissue.
The visceral serous pericardium, also known as the epicardium, covers the myocardium of the heart [8] and can be considered its serosa. It is largely made of a mesothelium overlying some elastin-rich loose connective tissue. During ventricular contraction, the wave of depolarization moves from the endocardial to the epicardial surface.