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A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart. Heart valves are opened or closed by a difference in blood pressure on each side. [1] [2] [3]
The cardiomyocytes make up the bulk (99%) of cells in the atria and ventricles. These contractile cells respond to impulses of action potential from the pacemaker cells and are responsible for the contractions that pump blood through the body. The pacemaker cells make up just (1% of cells) and form the conduction system of the heart.
Heart valves can malfunction for a variety of reasons, which can impede the flow of blood through the valve and/or let blood flow backwards through the valve (regurgitation). Both processes put strain on the heart and may lead to serious problems, including heart failure. While some dysfunctional valves can be treated with drugs or repaired ...
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
The mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles. [1] In normal conditions, blood flows through an open mitral valve during diastole with contraction of the left atrium, and the mitral valve closes during systole with contraction of the left ventricle. The ...
Blood is 92% water by weight and the rest of blood is composed of protein, nutrients, electrolytes, wastes, and dissolved gases. Depending on the health of an individual, the blood viscosity can vary (i.e., anemia causing relatively lower concentrations of protein, high blood pressure an increase in dissolved salts or lipids, etc.).
Blood flow through the valves Blood flow through the heart Video explanation of blood flow through the heart. The heart functions as a pump in the circulatory system to provide a continuous flow of blood throughout the body. This circulation consists of the systemic circulation to and from the body and the pulmonary circulation to and from the ...
A valve system in place here prevents the absorbed lymph from leaking back into the interstital fluid. This valve system involves collagen fibers attached to lymphatic endothelial cells that respond to increased interstitial fluid pressure by separating the endothelial cells and allowing the flow of lymph into the capillary for circulation. [5]