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As heart development continues, this tube undergoes remodeling to eventually form the four-chambered heart. The endocardial cushions are a subset of cells found in the developing heart tube that will give rise to the heart's primitive valves and septa , critical to the proper formation of a four-chambered heart.
The heart wall is made up of three layers: the inner endocardium, middle myocardium and outer epicardium. These are surrounded by a double-membraned sac called the pericardium. The innermost layer of the heart is called the endocardium. It is made up of a lining of simple squamous epithelium and covers heart chambers
The Sun is composed primarily of the chemical elements hydrogen and helium; they account for 74.9% and 23.8%, respectively, of the mass of the Sun in the photosphere.All heavier elements, colloquially called metals in stellar astronomy, account for less than 2% of the mass, with oxygen (roughly 1% of the Sun's mass), carbon (0.3%), neon (0.2%), and iron (0.2%) being the most abundant.
The pericardium (pl.: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. [1] It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium).
Illustration depicting the layers of the heart wall including the innermost endocardium. The endocardium (pl.: endocardia) is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the ...
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 ...
The Purkinje fibers, named for Jan Evangelista Purkyně, (English: / p ɜːr ˈ k ɪ n dʒ i / pur-KIN-jee; [1] Czech: [ˈpurkɪɲɛ] ⓘ; Purkinje tissue or subendocardial branches) are located in the inner ventricular walls of the heart, [2] just beneath the endocardium in a space called the subendocardium.
This is the strongest part of the fibrous cardiac skeleton. The upper chambers ( atria ) and lower ( ventricles ) 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 electrical propagation.