|
![](https://webarchive.library.unt.edu/eot2008/20080923071315im_/http://www.ncbi.nlm.nih.gov/books/bookres.fcgi/gnd/heart.jpg) Oxygen is vital to life as it provides fuel for all the body's functions. The heart's role
is to pump oxygen-rich blood to every cell in the body. The blood vessels a network of
interconnecting arteries, arterioles, capillaries, venules, and veins provide the pathway in which
blood travels. Arteries are the passageways through which the blood is delivered, the largest of which
is the aorta. The aorta branches off the heart and divides into many smaller arteries, which
have muscular walls that adjust their diameter to increase or decrease blood flow to a
particular body area. Capillaries are thin walled, highly branched vessels that feed
the tissues and collect wastes to be carried back to the lungs, liver, or kidney for
elimination. Capillaries empty into the venules, which in turn drain into the veins that
lead back to the heart. Veins carry deoxygenated blood to the lungs to pick up more oxygen,
and then back to the heart once again. The four most common types of vascular disease are high blood pressure, coronary heart
disease, stroke, and rheumatic heart disease. Other forms include arrhythmias, diseases
of the arteries, arterioles and capillaries, congenital defects, valvular heart disease,
diseases of pulmonary circulation; and diseases of veins and lymphatics. Some of these
disorders are the result of the over production of blood vessel cells, while others occur
from vascular malformations. Still others result from inflammation of the blood vessels
or the build up of a fatty substance called plaque within the blood vessels.![top link](https://webarchive.library.unt.edu/eot2008/20080923071315im_/http://www.ncbi.nlm.nih.gov/books/bookres.fcgi/system_default/top.gif)
|
|