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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]
Blood is flowing into the right atrium from the superior and inferior venae cavae and the coronary sinus. Blood flows into the left atrium from the four pulmonary veins. The two atrioventricular valves, the tricuspid and mitral valves, are both open, so blood flows unimpeded from the atria and into the ventricles.
Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste and carbon dioxide away from the tissues. [ 2 ] Some tissues such as cartilage , epithelium , and the lens and cornea of the eye are not supplied with blood vessels and are termed avascular .
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 ...
Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillaries—where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide—before being ...
One of the major drawbacks of mechanical heart valves is that they are associated with an increased risk of blood clots. Clots formed by red blood cell and platelet damage can block blood vessels leading to stroke. People with mechanical valves need to take anticoagulants (blood thinners), such as warfarin, for the rest of their life. [16]
The most common treatments are medications and surgery to repair the damaged blood vessels in your brain. Valvular heart disease Heart valve problems may be treated with medications or surgery.
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).