Physiology 2130 Lecture Notes - Blood Vessel, Pulmonary Circulation, Theca Interna
25 Feb 2013
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Document Summary
Blood vessels: it is through these that the blood is pumped and distributed to all areas of the body. The circulatory system is essentially a closed system of tubes (blood vessels) filled with fluid (blood) that is moved around by a central pump (the heart). The blood vessels consist of : arteries and arterioles that transport the blood away from the heart, capillaries where gas exchange takes place, venules and veins that return the blood back to the heart. The large arteries branch into smaller arteries, which eventually turn into smaller arterioles. These arterioles also branch into smaller vessels that lead to the capillaries. Capillaries are the smallest of all the blood vessels and are the functional units of the circulatory system where substances enter and leave. The capillaries converge into small venules, which get larger and larger to form veins. There are two principal loops that the blood takes through the body.
