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The heart is the driver of the circulatory system, pumping blood through rhythmic contraction and relaxation. The rate of blood flow out of the heart (often expressed in L/min) is known as the cardiac output (CO). Blood being pumped out of the heart first enters the aorta, the largest artery of the body.
For example, when standing up, the knees are extended. When a joint can move forward and backward, such as the neck and trunk, extension is movement in the posterior direction. [10] Extension of the hip or shoulder moves the arm or leg backward. [11] Even for other upper extremity joints – elbow and wrist, backward movement results in extension.
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).
Coronary arteries supply blood to the myocardium and other components of the heart. Two coronary arteries originate from the left side of the heart at the beginning (root) left ventricle . There are three aortic sinuses (dilations) in the wall of the aorta just superior to the aortic semilunar valve.
An experiment from Harvey's Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus. Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Latin, 'An Anatomical Exercise on the Motion of the Heart and Blood in Living Beings'), commonly called De Motu Cordis, is the best-known work of the physician William Harvey, which was first published in 1628 and established the ...
In 1920, August Krogh was awarded the Nobel Prize in Physiology or Medicine for his discovering the mechanism of regulation of capillaries in skeletal muscle. [6] [7] Krogh was the first to describe the adaptation of blood perfusion in muscle and other organs according to demands through the opening and closing of arterioles and capillaries.
Blood vessels play a huge role in virtually every medical condition. Cancer, for example, cannot progress unless the tumor causes angiogenesis (formation of new blood vessels) to supply the malignant cells' metabolic demand. [32] Atherosclerosis represents around 85% of all deaths from cardiovascular diseases due to the buildup of plaque. [33]
As they proceed forward and in their course are joined by other capillaries, they grow larger and first take on an adventitia, and then smooth muscles. The lymphatic conducting system broadly consists of two types of channels—the initial lymphatics , the prelymphatics or lymph capillaries that specialize in collection of the lymph from the ...