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Heart Structure

Heart Structure. Artery Wall Structure. The structure of the artery wall consists on three layers : the tunica adventitia , tunica media and the tunica intima.

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Heart Structure

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  1. HeartStructure

  2. Artery Wall Structure • Thestructure of thearterywallconsistsonthreelayers: thetunicaadventitia, tunica media and thetunica intima. • Tunicaadventitia: Strongoutercover of arteries. It has connectivetissue as well as elasticfibres, thesefibresallowthearterytostretch in ordertopreventoverexpansionbecause of thehighpressure. • Tunica media: Composed of smoothmuscle and elasticfibres. Thislayeristhicker in arteriesthan in veins. • Tunica intima: composed of an elastic membrane lining and smooth endothelium that is covered by elastic tissues.

  3. Veins Wall Structure • The veins wall is a lot like the arteries wall, it also consists of three layers called tunica adventitia, tunica media and tunica intima. • Tunica adventitia: the same as in the arteries, it contains collagen and eslasticfibres in order to sustain the high pressure. • Tunica media: the middle layer of the veins wall. It is composed of smooth muscles and elastic tissue. • Tunica intima: Veins do not contain the elastic membrane lining that is found in arteries. In veins the tunica intima layer also contains valves to keep blood flowing in a single direction.

  4. DifferencesbetweenArterywalls and Veinwalls • The arteries have a smaller lumen so that blood is under higher pressure, so it can be pumped all around the body. Veins have a larger lumen because it doesn’t’ need much pressure for the blood as it is contains deoxygenated blood. • The endothelium in the artery is folded allowing it to expand so that it can cope under high pressure from the blood, the veins endothelium isn’t folded because it doesn’t need to expand as blood is not under so much pressure. • The artery has a thick muscle layer so that it can cope with the high pressure of blood whereas the vein only has a thin muscle layer in its wall as it is not under so much pressure from the blood.

  5. Capillaries • A capillary is an extremely small blood vessel located within the tissues of the body, that transports blood from arteries to veins. • Capillary walls are thin and are composed of endothelium. Oxygen, carbon dioxide, nutrients and wastes are exchanged through the thin walls of the capillaries. • Capillaries play an important role in microcirculation. Microcirculation deals with the circulation of blood from the heart to arteries, to smaller arterioles, to capillaries, to venules, to veins and back to the heart.

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