Human cardiovascular system

The cardiovascular system includes the heart, the blood and the blood vessels. The heart pumps blood, and the blood vessels channel and supply it all over the body. Blood vessels are of three types. The first type i. e. arteries carry blood filled up with nutrients away from the heart to all locations of the body. The blood is usually compared to a river, but the arteries are more like a river in invert. Arteries are thick-walled tubes with a spherical covering of yellow, elastic fibers, which comprise a stuffing of muscle that absorbs the great stress wave of a heartbeat and slows the blood down. This pressure can be experienced in the arm and wrist. Subsequently arteries separate into smaller arterioles and then into even smaller capillaries, the tiniest of all blood vessels, which make the second type of blood vessels. One arteriole can serve a hundred capillaries. Here, in every tissue of every organ, blood's work is done when it gives up what the cells want and removes the waste products that they don't desire. Now the river consideration really does apply. Capillaries join together to form small veins, the third type of blood vessels, which flow into much bigger principal veins, and these deliver deoxygenated blood back to the heart. Veins, as opposed to arteries, have slim, slack walls, because the blood has lost the pressure which forced it out of the heart, so the dark, reddish-blue blood which flows through the veins on its way to the lungs oozes along very slowly on its way to be oxygenated. Back at the heart, the veins enter a special vessel, called the pulmonary arteries, into the wall at right side of the heart. It runs along the pulmonary arteries to the lungs to pick up oxygen, then back to the heart's left side to begin its journey all-around the body again.
The heart itself is strong muscular pumping organ that has of four chambers. It is very strong and hardly rests throughout the existence of an individual. Microscopically, the heart is composed of special type of muscle fibers that are unique from all other muscle fibers observed in the body. These muscle fibers are known as cardiac muscles. The cardiac muscle makes the mass of the heart. On a larger point, the heart can be thought about as composed of three layers. The outermost layer is known as epicardium. The middle layer is the myocardium and the innermost layer is the endocardium.
Blood is a distinct form of tissue that is in fluid form. It consists of two major elements: plasma and formed elements. Plasma makes about 55% of blood and significant percentage of it is water. It also carries some essential proteins. The formed elements make about 45% of the blood. Three significant types of cells make this portion of the blood. These cells are Red blood cells, White blood cells and Platelets.
Cardiovascular system is an incredibly essential system of human body. Without a working cardiovascular system, human body can't carry on more than a minute or two. Heart, the most essential organ of human body after brain, is the principal part of this system. A healthy heart assures a healthy cardiovascular system which in turn assures a healthy life. It is well worth talking about here that according to CDC, the greatest cause of deaths in United States is heart diseases.

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