The Structure and Function Of Arteries, Veins and Capillaries

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The Structure and Function Of Arteries, Veins and Capillaries

In its route from the heart to the tissues, the blood passes through channels of six foremost types: elastic arteries, muscular arteries, arterioles, capillaries, venules and veins. I intend to explore the structure and function of arteries, veins and capillaries. When an artery branches into smaller and smaller vessels, eventually the blood vessel is too small to see with the naked eye. At that point, it is called an arteriole. Likewise, a venule is a microscopic vein.

Arteries

All arteries are comprised of three different layers but the proportion and structure of each varies with the size and function of the particular
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Arteries, because of their elastic nature can stretch with systole or relax with diastole. Their elastic property allows the arteries to oppose the force of the flow. The arteries can "control" (help form a pulsatile) the flow so that when blood reaches the arterioles and eventually the capillaries the stream of blood is milder. The wall of the arterioles contains less elastic fibres because the blood pressure within the arterioles is lower. Arterioles have more smooth muscle cells than large arteries, which allow blood to pass through them and on to the capillaries efficiently because friction is reduced.

Veins =====

Veins and venules are similar in structure to arteries and arterioles, however veins have a wider inner diameter, which means that they can hold a larger volume of blood. Since it would be unworkable to get all the blood back to the heart as quickly as it left the heart (because there is no pumping mechanism to do so); veins have to be able to hold more blood than arteries. The veins provide a "storage area" for our blood, which is why the diameter of the veins is larger than the artery diameter. At any given time, the majority of our blood is within our veins.

Veins have a thinner smooth muscle layer that allows for the expansion of the vessels and minimize resistance by reducing
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